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https://github.com/RPCS3/llvm-mirror.git
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83f99b8d3f
This patch improves the logic added at revision 224899 (see review D6728) that teaches the backend when it is profitable to speculate calls to cttz/ctlz. The original algorithm conservatively avoided speculating more than one instruction from a basic block in a control flow grap modelling an if-statement. In particular, the only allowed instruction (excluding the terminator) was a call to cttz/ctlz. However, there are cases where we could be less conservative and still be able to speculate a call to cttz/ctlz. With this patch, CodeGenPrepare now tries to speculate a cttz/ctlz if the result is zero extended/truncated in the same basic block, and the zext/trunc instruction is "free" for the target. Added new test cases to CodeGen/X86/cttz-ctlz.ll Differential Revision: http://reviews.llvm.org/D6853 llvm-svn: 225274
423 lines
13 KiB
LLVM
423 lines
13 KiB
LLVM
; RUN: opt -S -codegenprepare -mtriple=x86_64-unknown-unknown -mattr=+bmi < %s | FileCheck %s --check-prefix=ALL --check-prefix=BMI
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; RUN: opt -S -codegenprepare -mtriple=x86_64-unknown-unknown -mattr=+lzcnt < %s | FileCheck %s --check-prefix=ALL --check-prefix=LZCNT
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; RUN: opt -S -codegenprepare -mtriple=x86_64-unknown-unknown < %s | FileCheck %s --check-prefix=ALL --check-prefix=GENERIC
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define i64 @test1(i64 %A) {
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; ALL-LABEL: @test1(
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; LZCNT: [[CTLZ:%[A-Za-z0-9]+]] = call i64 @llvm.ctlz.i64(i64 %A, i1 false)
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; LZCNT-NEXT: ret i64 [[CTLZ]]
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; BMI: icmp eq i64 %A, 0
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; BMI: call i64 @llvm.ctlz.i64(i64 %A, i1 true)
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; GENERIC: icmp eq i64 %A, 0
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; GENERIC: call i64 @llvm.ctlz.i64(i64 %A, i1 true)
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entry:
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%tobool = icmp eq i64 %A, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i64 @llvm.ctlz.i64(i64 %A, i1 true)
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i64 [ %0, %cond.true ], [ 64, %entry ]
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ret i64 %cond
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}
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define i32 @test2(i32 %A) {
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; ALL-LABEL: @test2(
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; LZCNT: [[CTLZ:%[A-Za-z0-9]+]] = call i32 @llvm.ctlz.i32(i32 %A, i1 false)
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; LZCNT-NEXT: ret i32 [[CTLZ]]
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; BMI: icmp eq i32 %A, 0
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; BMI: call i32 @llvm.ctlz.i32(i32 %A, i1 true)
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; GENERIC: icmp eq i32 %A, 0
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; GENERIC: call i32 @llvm.ctlz.i32(i32 %A, i1 true)
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entry:
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%tobool = icmp eq i32 %A, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i32 @llvm.ctlz.i32(i32 %A, i1 true)
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i32 [ %0, %cond.true ], [ 32, %entry ]
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ret i32 %cond
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}
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define signext i16 @test3(i16 signext %A) {
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; ALL-LABEL: @test3(
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; LZCNT: [[CTLZ:%[A-Za-z0-9]+]] = call i16 @llvm.ctlz.i16(i16 %A, i1 false)
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; LZCNT-NEXT: ret i16 [[CTLZ]]
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; BMI: icmp eq i16 %A, 0
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; BMI: call i16 @llvm.ctlz.i16(i16 %A, i1 true)
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; GENERIC: icmp eq i16 %A, 0
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; GENERIC: call i16 @llvm.ctlz.i16(i16 %A, i1 true)
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entry:
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%tobool = icmp eq i16 %A, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i16 @llvm.ctlz.i16(i16 %A, i1 true)
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i16 [ %0, %cond.true ], [ 16, %entry ]
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ret i16 %cond
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}
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define i64 @test1b(i64 %A) {
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; ALL-LABEL: @test1b(
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; LZCNT: icmp eq i64 %A, 0
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; LZCNT: call i64 @llvm.cttz.i64(i64 %A, i1 true)
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; BMI: [[CTTZ:%[A-Za-z0-9]+]] = call i64 @llvm.cttz.i64(i64 %A, i1 false)
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; BMI-NEXT: ret i64 [[CTTZ]]
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; GENERIC: icmp eq i64 %A, 0
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; GENERIC: call i64 @llvm.cttz.i64(i64 %A, i1 true)
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entry:
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%tobool = icmp eq i64 %A, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i64 @llvm.cttz.i64(i64 %A, i1 true)
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i64 [ %0, %cond.true ], [ 64, %entry ]
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ret i64 %cond
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}
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define i32 @test2b(i32 %A) {
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; ALL-LABEL: @test2b(
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; LZCNT: icmp eq i32 %A, 0
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; LZCNT: call i32 @llvm.cttz.i32(i32 %A, i1 true)
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; BMI: [[CTTZ:%[A-Za-z0-9]+]] = call i32 @llvm.cttz.i32(i32 %A, i1 false)
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; BMI-NEXT: ret i32 [[CTTZ]]
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; GENERIC: icmp eq i32 %A, 0
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; GENERIC: call i32 @llvm.cttz.i32(i32 %A, i1 true)
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entry:
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%tobool = icmp eq i32 %A, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i32 @llvm.cttz.i32(i32 %A, i1 true)
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i32 [ %0, %cond.true ], [ 32, %entry ]
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ret i32 %cond
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}
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define signext i16 @test3b(i16 signext %A) {
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; ALL-LABEL: @test3b(
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; LZCNT: icmp eq i16 %A, 0
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; LZCNT: call i16 @llvm.cttz.i16(i16 %A, i1 true)
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; BMI: [[CTTZ:%[A-Za-z0-9]+]] = call i16 @llvm.cttz.i16(i16 %A, i1 false)
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; BMI-NEXT: ret i16 [[CTTZ]]
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; GENERIC: icmp eq i16 %A, 0
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; GENERIC: call i16 @llvm.cttz.i16(i16 %A, i1 true)
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entry:
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%tobool = icmp eq i16 %A, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i16 @llvm.cttz.i16(i16 %A, i1 true)
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i16 [ %0, %cond.true ], [ 16, %entry ]
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ret i16 %cond
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}
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define i64 @test1c(i64 %A) {
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; ALL-LABEL: @test1c(
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; ALL: icmp eq i64 %A, 0
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; ALL: call i64 @llvm.ctlz.i64(i64 %A, i1 true)
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entry:
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%tobool = icmp eq i64 %A, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i64 @llvm.ctlz.i64(i64 %A, i1 true)
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i64 [ %0, %cond.true ], [ 63, %entry ]
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ret i64 %cond
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}
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define i32 @test2c(i32 %A) {
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; ALL-LABEL: @test2c(
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; ALL: icmp eq i32 %A, 0
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; ALL: call i32 @llvm.ctlz.i32(i32 %A, i1 true)
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entry:
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%tobool = icmp eq i32 %A, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i32 @llvm.ctlz.i32(i32 %A, i1 true)
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i32 [ %0, %cond.true ], [ 31, %entry ]
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ret i32 %cond
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}
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define signext i16 @test3c(i16 signext %A) {
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; ALL-LABEL: @test3c(
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; ALL: icmp eq i16 %A, 0
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; ALL: call i16 @llvm.ctlz.i16(i16 %A, i1 true)
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entry:
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%tobool = icmp eq i16 %A, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i16 @llvm.ctlz.i16(i16 %A, i1 true)
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i16 [ %0, %cond.true ], [ 15, %entry ]
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ret i16 %cond
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}
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define i64 @test1d(i64 %A) {
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; ALL-LABEL: @test1d(
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; ALL: icmp eq i64 %A, 0
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; ALL: call i64 @llvm.cttz.i64(i64 %A, i1 true)
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entry:
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%tobool = icmp eq i64 %A, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i64 @llvm.cttz.i64(i64 %A, i1 true)
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i64 [ %0, %cond.true ], [ 63, %entry ]
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ret i64 %cond
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}
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define i32 @test2d(i32 %A) {
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; ALL-LABEL: @test2d(
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; ALL: icmp eq i32 %A, 0
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; ALL: call i32 @llvm.cttz.i32(i32 %A, i1 true)
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entry:
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%tobool = icmp eq i32 %A, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i32 @llvm.cttz.i32(i32 %A, i1 true)
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i32 [ %0, %cond.true ], [ 31, %entry ]
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ret i32 %cond
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}
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define signext i16 @test3d(i16 signext %A) {
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; ALL-LABEL: @test3d(
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; ALL: icmp eq i16 %A, 0
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; ALL: call i16 @llvm.cttz.i16(i16 %A, i1 true)
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entry:
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%tobool = icmp eq i16 %A, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i16 @llvm.cttz.i16(i16 %A, i1 true)
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i16 [ %0, %cond.true ], [ 15, %entry ]
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ret i16 %cond
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}
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; The following tests verify that calls to cttz/ctlz are speculated even if
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; basic block %cond.true has an extra zero extend/truncate which is "free"
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; for the target.
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define i64 @test1e(i32 %x) {
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; ALL-LABEL: @test1e(
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; LZCNT: icmp eq i32 %x, 0
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; LZCNT: call i32 @llvm.cttz.i32(i32 %x, i1 true)
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; BMI: call i32 @llvm.cttz.i32(i32 %x, i1 false)
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; GENERIC: icmp eq i32 %x, 0
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; GENERIC: call i32 @llvm.cttz.i32(i32 %x, i1 true)
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entry:
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%tobool = icmp eq i32 %x, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i32 @llvm.cttz.i32(i32 %x, i1 true)
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%phitmp2 = zext i32 %0 to i64
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i64 [ %phitmp2, %cond.true ], [ 32, %entry ]
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ret i64 %cond
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}
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define i32 @test2e(i64 %x) {
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; ALL-LABEL: @test2e(
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; LZCNT: icmp eq i64 %x, 0
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; LZCNT: call i64 @llvm.cttz.i64(i64 %x, i1 true)
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; BMI: call i64 @llvm.cttz.i64(i64 %x, i1 false)
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; GENERIC: icmp eq i64 %x, 0
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; GENERIC: call i64 @llvm.cttz.i64(i64 %x, i1 true)
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entry:
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%tobool = icmp eq i64 %x, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i64 @llvm.cttz.i64(i64 %x, i1 true)
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%cast = trunc i64 %0 to i32
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i32 [ %cast, %cond.true ], [ 64, %entry ]
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ret i32 %cond
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}
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define i64 @test3e(i32 %x) {
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; ALL-LABEL: @test3e(
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; BMI: icmp eq i32 %x, 0
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; BMI: call i32 @llvm.ctlz.i32(i32 %x, i1 true)
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; LZCNT: call i32 @llvm.ctlz.i32(i32 %x, i1 false)
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; GENERIC: icmp eq i32 %x, 0
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; GENERIC: call i32 @llvm.ctlz.i32(i32 %x, i1 true)
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entry:
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%tobool = icmp eq i32 %x, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i32 @llvm.ctlz.i32(i32 %x, i1 true)
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%phitmp2 = zext i32 %0 to i64
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i64 [ %phitmp2, %cond.true ], [ 32, %entry ]
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ret i64 %cond
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}
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define i32 @test4e(i64 %x) {
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; ALL-LABEL: @test4e(
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; BMI: icmp eq i64 %x, 0
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; BMI: call i64 @llvm.ctlz.i64(i64 %x, i1 true)
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; LZCNT: call i64 @llvm.ctlz.i64(i64 %x, i1 false)
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; GENERIC: icmp eq i64 %x, 0
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; GENERIC: call i64 @llvm.ctlz.i64(i64 %x, i1 true)
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entry:
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%tobool = icmp eq i64 %x, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i64 @llvm.ctlz.i64(i64 %x, i1 true)
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%cast = trunc i64 %0 to i32
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i32 [ %cast, %cond.true ], [ 64, %entry ]
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ret i32 %cond
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}
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define i16 @test5e(i64 %x) {
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; ALL-LABEL: @test5e(
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; BMI: icmp eq i64 %x, 0
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; BMI: call i64 @llvm.ctlz.i64(i64 %x, i1 true)
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; LZCNT: call i64 @llvm.ctlz.i64(i64 %x, i1 false)
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; GENERIC: icmp eq i64 %x, 0
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; GENERIC: call i64 @llvm.ctlz.i64(i64 %x, i1 true)
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entry:
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%tobool = icmp eq i64 %x, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i64 @llvm.ctlz.i64(i64 %x, i1 true)
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%cast = trunc i64 %0 to i16
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i16 [ %cast, %cond.true ], [ 64, %entry ]
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ret i16 %cond
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}
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define i16 @test6e(i32 %x) {
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; ALL-LABEL: @test6e(
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; BMI: icmp eq i32 %x, 0
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; BMI: call i32 @llvm.ctlz.i32(i32 %x, i1 true)
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; LZCNT: call i32 @llvm.ctlz.i32(i32 %x, i1 false)
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; GENERIC: icmp eq i32 %x, 0
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; GENERIC: call i32 @llvm.ctlz.i32(i32 %x, i1 true)
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entry:
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%tobool = icmp eq i32 %x, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i32 @llvm.ctlz.i32(i32 %x, i1 true)
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%cast = trunc i32 %0 to i16
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i16 [ %cast, %cond.true ], [ 32, %entry ]
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ret i16 %cond
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}
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define i16 @test7e(i64 %x) {
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; ALL-LABEL: @test7e(
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; LZCNT: icmp eq i64 %x, 0
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; LZCNT: call i64 @llvm.cttz.i64(i64 %x, i1 true)
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; BMI: call i64 @llvm.cttz.i64(i64 %x, i1 false)
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; GENERIC: icmp eq i64 %x, 0
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; GENERIC: call i64 @llvm.cttz.i64(i64 %x, i1 true)
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entry:
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%tobool = icmp eq i64 %x, 0
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br i1 %tobool, label %cond.end, label %cond.true
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cond.true: ; preds = %entry
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%0 = tail call i64 @llvm.cttz.i64(i64 %x, i1 true)
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%cast = trunc i64 %0 to i16
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br label %cond.end
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cond.end: ; preds = %entry, %cond.true
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%cond = phi i16 [ %cast, %cond.true ], [ 64, %entry ]
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ret i16 %cond
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}
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define i16 @test8e(i32 %x) {
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; ALL-LABEL: @test8e(
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; LZCNT: icmp eq i32 %x, 0
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; LZCNT: call i32 @llvm.cttz.i32(i32 %x, i1 true)
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; BMI: call i32 @llvm.cttz.i32(i32 %x, i1 false)
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; GENERIC: icmp eq i32 %x, 0
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; GENERIC: call i32 @llvm.cttz.i32(i32 %x, i1 true)
|
|
entry:
|
|
%tobool = icmp eq i32 %x, 0
|
|
br i1 %tobool, label %cond.end, label %cond.true
|
|
|
|
cond.true: ; preds = %entry
|
|
%0 = tail call i32 @llvm.cttz.i32(i32 %x, i1 true)
|
|
%cast = trunc i32 %0 to i16
|
|
br label %cond.end
|
|
|
|
cond.end: ; preds = %entry, %cond.true
|
|
%cond = phi i16 [ %cast, %cond.true ], [ 32, %entry ]
|
|
ret i16 %cond
|
|
}
|
|
|
|
|
|
declare i64 @llvm.ctlz.i64(i64, i1)
|
|
declare i32 @llvm.ctlz.i32(i32, i1)
|
|
declare i16 @llvm.ctlz.i16(i16, i1)
|
|
declare i64 @llvm.cttz.i64(i64, i1)
|
|
declare i32 @llvm.cttz.i32(i32, i1)
|
|
declare i16 @llvm.cttz.i16(i16, i1)
|