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https://github.com/RPCS3/llvm-mirror.git
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812a2fc1c7
Summary: This patch allows JumpThreading also thread through guards. Virtually, guard(cond) is equivalent to the following construction: if (cond) { do something } else {deoptimize} Yet it is not explicitly converted into IFs before lowering. This patch enables early threading through guards in simple cases. Currently it covers the following situation: if (cond1) { // code A } else { // code B } // code C guard(cond2) // code D If there is implication cond1 => cond2 or !cond1 => cond2, we can transform this construction into the following: if (cond1) { // code A // code C } else { // code B // code C guard(cond2) } // code D Thus, removing the guard from one of execution branches. Patch by Max Kazantsev! Reviewers: reames, apilipenko, igor-laevsky, anna, sanjoy Reviewed By: sanjoy Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D29620 llvm-svn: 294617
133 lines
3.5 KiB
LLVM
133 lines
3.5 KiB
LLVM
; RUN: opt < %s -jump-threading -dce -S | FileCheck %s
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declare void @llvm.experimental.guard(i1, ...)
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declare i32 @f1()
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declare i32 @f2()
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define i32 @branch_implies_guard(i32 %a) {
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; CHECK-LABEL: @branch_implies_guard(
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%cond = icmp slt i32 %a, 10
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br i1 %cond, label %T1, label %F1
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T1:
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; CHECK: T1.split
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; CHECK: %v1 = call i32 @f1()
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; CHECK-NEXT: %retVal
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; CHECK-NEXT: br label %Merge
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%v1 = call i32 @f1()
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br label %Merge
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F1:
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; CHECK: F1.split
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; CHECK: %v2 = call i32 @f2()
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; CHECK-NEXT: %retVal
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; CHECK-NEXT: %condGuard
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; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %condGuard
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; CHECK-NEXT: br label %Merge
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%v2 = call i32 @f2()
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br label %Merge
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Merge:
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; CHECK: Merge
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; CHECK-NOT: call void(i1, ...) @llvm.experimental.guard(
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%retPhi = phi i32 [ %v1, %T1 ], [ %v2, %F1 ]
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%retVal = add i32 %retPhi, 10
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%condGuard = icmp slt i32 %a, 20
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call void(i1, ...) @llvm.experimental.guard( i1 %condGuard )[ "deopt"() ]
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ret i32 %retVal
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}
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define i32 @not_branch_implies_guard(i32 %a) {
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; CHECK-LABEL: @not_branch_implies_guard(
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%cond = icmp slt i32 %a, 20
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br i1 %cond, label %T1, label %F1
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T1:
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; CHECK: T1.split:
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; CHECK-NEXT: %v1 = call i32 @f1()
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; CHECK-NEXT: %retVal
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; CHECK-NEXT: %condGuard
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; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %condGuard
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; CHECK-NEXT: br label %Merge
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%v1 = call i32 @f1()
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br label %Merge
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F1:
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; CHECK: F1.split:
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; CHECK-NEXT: %v2 = call i32 @f2()
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; CHECK-NEXT: %retVal
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; CHECK-NEXT: br label %Merge
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%v2 = call i32 @f2()
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br label %Merge
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Merge:
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; CHECK: Merge
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; CHECK-NOT: call void(i1, ...) @llvm.experimental.guard(
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%retPhi = phi i32 [ %v1, %T1 ], [ %v2, %F1 ]
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%retVal = add i32 %retPhi, 10
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%condGuard = icmp sgt i32 %a, 10
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call void(i1, ...) @llvm.experimental.guard( i1 %condGuard )[ "deopt"() ]
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ret i32 %retVal
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}
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define i32 @branch_overlaps_guard(i32 %a) {
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; CHECK-LABEL: @branch_overlaps_guard(
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%cond = icmp slt i32 %a, 20
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br i1 %cond, label %T1, label %F1
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T1:
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; CHECK: T1:
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; CHECK-NEXT: %v1 = call i32 @f1()
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; CHECK-NEXT: br label %Merge
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%v1 = call i32 @f1()
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br label %Merge
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F1:
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; CHECK: F1:
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; CHECK-NEXT: %v2 = call i32 @f2()
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; CHECK-NEXT: br label %Merge
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%v2 = call i32 @f2()
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br label %Merge
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Merge:
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; CHECK: Merge
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; CHECK: %condGuard = icmp slt i32 %a, 10
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; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %condGuard) [ "deopt"() ]
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%retPhi = phi i32 [ %v1, %T1 ], [ %v2, %F1 ]
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%retVal = add i32 %retPhi, 10
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%condGuard = icmp slt i32 %a, 10
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call void(i1, ...) @llvm.experimental.guard( i1 %condGuard )[ "deopt"() ]
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ret i32 %retVal
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}
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define i32 @branch_doesnt_overlap_guard(i32 %a) {
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; CHECK-LABEL: @branch_doesnt_overlap_guard(
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%cond = icmp slt i32 %a, 10
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br i1 %cond, label %T1, label %F1
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T1:
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; CHECK: T1:
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; CHECK-NEXT: %v1 = call i32 @f1()
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; CHECK-NEXT: br label %Merge
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%v1 = call i32 @f1()
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br label %Merge
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F1:
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; CHECK: F1:
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; CHECK-NEXT: %v2 = call i32 @f2()
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; CHECK-NEXT: br label %Merge
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%v2 = call i32 @f2()
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br label %Merge
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Merge:
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; CHECK: Merge
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; CHECK: %condGuard = icmp sgt i32 %a, 20
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; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %condGuard) [ "deopt"() ]
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%retPhi = phi i32 [ %v1, %T1 ], [ %v2, %F1 ]
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%retVal = add i32 %retPhi, 10
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%condGuard = icmp sgt i32 %a, 20
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call void(i1, ...) @llvm.experimental.guard( i1 %condGuard )[ "deopt"() ]
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ret i32 %retVal
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}
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