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llvm-mirror/test/Analysis/ScalarEvolution/guards.ll
Max Kazantsev 9e73a14fba Re-enable "[IndVars] Canonicalize comparisons between non-negative values and indvars"
The patch was reverted due to a bug. The bug was that if the IV is the 2nd operand of the icmp
instruction, then the "Pred" variable gets swapped and differs from the instruction's predicate.
In this patch we use the original predicate to do the transformation.

Also added a test case that exercises this situation.

Differentian Revision: https://reviews.llvm.org/D35107

llvm-svn: 307477
2017-07-08 17:17:30 +00:00

142 lines
4.0 KiB
LLVM

; RUN: opt -S -indvars < %s | FileCheck %s
; Check that SCEV is able to recognize and use guards to prove
; conditions gaurding loop entries and backedges. This isn't intended
; to be a comprehensive test of SCEV's simplification capabilities,
; tests directly testing e.g. if SCEV can elide a sext should go
; elsewhere.
target datalayout = "n8:16:32:64"
declare void @llvm.experimental.guard(i1, ...)
define void @test_1(i1* %cond_buf, i32* %len_buf) {
; CHECK-LABEL: @test_1(
entry:
%len = load i32, i32* %len_buf, !range !{i32 1, i32 2147483648}
br label %loop
loop:
; CHECK: loop:
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 true) [ "deopt"() ]
; CHECK: %iv.inc.cmp = icmp ult i32 %iv.inc, %len
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %iv.inc.cmp) [ "deopt"() ]
; CHECK: leave:
%iv = phi i32 [ 0, %entry ], [ %iv.inc, %loop ]
%iv.inc = add i32 %iv, 1
%iv.cmp = icmp slt i32 %iv, %len
call void(i1, ...) @llvm.experimental.guard(i1 %iv.cmp) [ "deopt"() ]
%iv.inc.cmp = icmp slt i32 %iv.inc, %len
call void(i1, ...) @llvm.experimental.guard(i1 %iv.inc.cmp) [ "deopt"() ]
%becond = load volatile i1, i1* %cond_buf
br i1 %becond, label %loop, label %leave
leave:
ret void
}
define void @test_2(i32 %n, i32* %len_buf) {
; CHECK-LABEL: @test_2(
; CHECK: [[LEN_ZEXT:%[^ ]+]] = zext i32 %len to i64
; CHECK: br label %loop
entry:
%len = load i32, i32* %len_buf, !range !{i32 0, i32 2147483648}
br label %loop
loop:
; CHECK: loop:
; CHECK: %indvars.iv = phi i64 [ %indvars.iv.next, %loop ], [ 0, %entry ]
; CHECK: %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
; CHECK: %iv.inc.cmp = icmp ult i64 %indvars.iv.next, [[LEN_ZEXT]]
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %iv.inc.cmp) [ "deopt"() ]
; CHECK: leave:
%iv = phi i32 [ 0, %entry ], [ %iv.inc, %loop ]
%iv.inc = add i32 %iv, 1
%iv.sext = sext i32 %iv to i64
%iv.inc.cmp = icmp slt i32 %iv.inc, %len
call void(i1, ...) @llvm.experimental.guard(i1 %iv.inc.cmp) [ "deopt"() ]
%becond = icmp ne i32 %iv, %n
br i1 %becond, label %loop, label %leave
leave:
ret void
}
define void @test_3(i1* %cond_buf, i32* %len_buf) {
; CHECK-LABEL: @test_3(
entry:
%len = load i32, i32* %len_buf
%entry.cond = icmp sgt i32 %len, 0
call void(i1, ...) @llvm.experimental.guard(i1 %entry.cond) [ "deopt"() ]
br label %loop
loop:
; CHECK: loop:
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 true) [ "deopt"() ]
; CHECK: %iv.inc.cmp = icmp slt i32 %iv.inc, %len
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %iv.inc.cmp) [ "deopt"() ]
; CHECK: leave:
%iv = phi i32 [ 0, %entry ], [ %iv.inc, %loop ]
%iv.inc = add i32 %iv, 1
%iv.cmp = icmp slt i32 %iv, %len
call void(i1, ...) @llvm.experimental.guard(i1 %iv.cmp) [ "deopt"() ]
%iv.inc.cmp = icmp slt i32 %iv.inc, %len
call void(i1, ...) @llvm.experimental.guard(i1 %iv.inc.cmp) [ "deopt"() ]
%becond = load volatile i1, i1* %cond_buf
br i1 %becond, label %loop, label %leave
leave:
ret void
}
define void @test_4(i1* %cond_buf, i32* %len_buf) {
; CHECK-LABEL: @test_4(
entry:
%len = load i32, i32* %len_buf
%entry.cond = icmp sgt i32 %len, 0
call void(i1, ...) @llvm.experimental.guard(i1 %entry.cond) [ "deopt"() ]
br label %loop
loop:
%iv = phi i32 [ 0, %entry ], [ %iv.inc, %be ]
%iv.inc = add i32 %iv, 1
%cond = load volatile i1, i1* %cond_buf
br i1 %cond, label %left, label %be
left:
; Does not dominate the backedge, so cannot be used in the inductive proof
%iv.inc.cmp = icmp slt i32 %iv.inc, %len
call void(i1, ...) @llvm.experimental.guard(i1 %iv.inc.cmp) [ "deopt"() ]
br label %be
be:
; CHECK: be:
; CHECK-NEXT: %iv.cmp = icmp slt i32 %iv, %len
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %iv.cmp) [ "deopt"() ]
; CHECK: leave:
%iv.cmp = icmp slt i32 %iv, %len
call void(i1, ...) @llvm.experimental.guard(i1 %iv.cmp) [ "deopt"() ]
%becond = load volatile i1, i1* %cond_buf
br i1 %becond, label %loop, label %leave
leave:
ret void
}