[llvm] c8eb83f - [ControlHeightReduction] Use logical and

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2022-05-26T18:03:35+02:00
New Revision: c8eb83f2d007dd3279a9ff459f3464a3cd9568b6

URL: https://github.com/llvm/llvm-project/commit/c8eb83f2d007dd3279a9ff459f3464a3cd9568b6
DIFF: https://github.com/llvm/llvm-project/commit/c8eb83f2d007dd3279a9ff459f3464a3cd9568b6.diff

LOG: [ControlHeightReduction] Use logical and

Use logical instead of bitwise and to combine conditions, to avoid
propagating poison from a later condition if an earlier one is
already false. This avoids introducing branch on poison.

Differential Revision: https://reviews.llvm.org/D125898

Added: 
    

Modified: 
    llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp
    llvm/test/Transforms/PGOProfile/chr.ll

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp b/llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp
index 2d1b76293272b..9611342d1c7ce 100644
--- a/llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp
+++ b/llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp
@@ -1981,7 +1981,8 @@ void CHR::addToMergedCondition(bool IsTrueBiased, Value *Cond,
       !isGuaranteedNotToBeUndefOrPoison(Cond))
     Cond = IRB.CreateFreeze(Cond);
 
-  MergedCondition = IRB.CreateAnd(MergedCondition, Cond);
+  // Use logical and to avoid propagating poison from later conditions.
+  MergedCondition = IRB.CreateLogicalAnd(MergedCondition, Cond);
 }
 
 void CHR::transformScopes(SmallVectorImpl<CHRScope *> &CHRScopes) {

diff  --git a/llvm/test/Transforms/PGOProfile/chr.ll b/llvm/test/Transforms/PGOProfile/chr.ll
index 18fd7c0182a58..e412ec5f8805f 100644
--- a/llvm/test/Transforms/PGOProfile/chr.ll
+++ b/llvm/test/Transforms/PGOProfile/chr.ll
@@ -553,7 +553,7 @@ define i32 @test_chr_5_1(i32* %i, i32 %sum0) !prof !14 {
 ; CHECK-NEXT:    [[TMP2:%.*]] = icmp ne i32 [[TMP1]], 0
 ; CHECK-NEXT:    [[TMP3:%.*]] = and i32 [[DOTFR1]], 11
 ; CHECK-NEXT:    [[TMP4:%.*]] = icmp eq i32 [[TMP3]], 11
-; CHECK-NEXT:    [[TMP5:%.*]] = and i1 [[TMP4]], [[TMP2]]
+; CHECK-NEXT:    [[TMP5:%.*]] = select i1 [[TMP4]], i1 [[TMP2]], i1 false
 ; CHECK-NEXT:    br i1 [[TMP5]], label [[BB0:%.*]], label [[ENTRY_SPLIT_NONCHR:%.*]], !prof [[PROF15]]
 ; CHECK:       bb0:
 ; CHECK-NEXT:    [[TMP6:%.*]] = add i32 [[SUM0]], 85
@@ -655,7 +655,7 @@ define i32 @test_chr_6(i32* %i, i32* %j, i32 %sum0) !prof !14 {
 ; CHECK-NEXT:    [[V10:%.*]] = icmp ne i32 [[V9]], 0
 ; CHECK-NEXT:    [[TMP0:%.*]] = and i32 [[I0_FR]], 10
 ; CHECK-NEXT:    [[TMP1:%.*]] = icmp eq i32 [[TMP0]], 10
-; CHECK-NEXT:    [[TMP2:%.*]] = and i1 [[TMP1]], [[V10]]
+; CHECK-NEXT:    [[TMP2:%.*]] = select i1 [[TMP1]], i1 [[V10]], i1 false
 ; CHECK-NEXT:    br i1 [[TMP2]], label [[BB0:%.*]], label [[ENTRY_SPLIT_NONCHR:%.*]], !prof [[PROF15]]
 ; CHECK:       bb0:
 ; CHECK-NEXT:    [[V8:%.*]] = add i32 [[SUM0:%.*]], 43
@@ -1123,7 +1123,7 @@ define void @test_chr_11(i32* %i, i32 %x) !prof !14 {
 ; CHECK-NEXT:    [[MUL16:%.*]] = fmul double [[DIV]], [[CONV]]
 ; CHECK-NEXT:    [[CONV717:%.*]] = fptosi double [[MUL16]] to i32
 ; CHECK-NEXT:    [[CMP18:%.*]] = icmp sgt i32 [[CONV717]], 0
-; CHECK-NEXT:    [[TMP3:%.*]] = and i1 [[TMP2]], [[CMP18]]
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[TMP2]], i1 [[CMP18]], i1 false
 ; CHECK-NEXT:    br i1 [[TMP3]], label [[BB0:%.*]], label [[ENTRY_SPLIT_NONCHR:%.*]], !prof [[PROF15]]
 ; CHECK:       bb0:
 ; CHECK-NEXT:    call void @foo()
@@ -1919,8 +1919,8 @@ define i32 @test_chr_21(i64 %i, i64 %k, i64 %j) !prof !14 {
 ; CHECK-NEXT:    [[CMP0:%.*]] = icmp ne i64 [[J:%.*]], [[K:%.*]]
 ; CHECK-NEXT:    [[CMP3:%.*]] = icmp ne i64 [[J]], [[I:%.*]]
 ; CHECK-NEXT:    [[CMP_I:%.*]] = icmp ne i64 [[I]], 86
-; CHECK-NEXT:    [[TMP0:%.*]] = and i1 [[CMP0]], [[CMP3]]
-; CHECK-NEXT:    [[TMP1:%.*]] = and i1 [[TMP0]], [[CMP_I]]
+; CHECK-NEXT:    [[TMP0:%.*]] = select i1 [[CMP0]], i1 [[CMP3]], i1 false
+; CHECK-NEXT:    [[TMP1:%.*]] = select i1 [[TMP0]], i1 [[CMP_I]], i1 false
 ; CHECK-NEXT:    br i1 [[TMP1]], label [[BB1:%.*]], label [[ENTRY_SPLIT_NONCHR:%.*]], !prof [[PROF15]]
 ; CHECK:       bb1:
 ; CHECK-NEXT:    [[CMP2:%.*]] = icmp ne i64 [[I]], 2