[NewGVN] Fold equivalent freeze instructions

Differential Revision: https://reviews.llvm.org/D152529
llvm · Jun 9, 2023 · c0ad1b4 · c0ad1b4
1 parent b27b5dc
commit c0ad1b4
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Showing 2 changed files with 4 additions and 6 deletions.
diff --git a/llvm/lib/Transforms/Scalar/NewGVN.cpp b/llvm/lib/Transforms/Scalar/NewGVN.cpp
@@ -1994,6 +1994,7 @@ NewGVN::performSymbolicEvaluation(Value *V,
       break;
     case Instruction::BitCast:
     case Instruction::AddrSpaceCast:
+    case Instruction::Freeze:
       return createExpression(I);
       break;
     case Instruction::ICmp:

diff --git a/llvm/test/Transforms/NewGVN/freeze.ll b/llvm/test/Transforms/NewGVN/freeze.ll
@@ -4,9 +4,7 @@
 define i1 @f(i1 %a) {
 ; CHECK-LABEL: @f(
 ; CHECK-NEXT:    [[B:%.*]] = freeze i1 [[A:%.*]]
-; CHECK-NEXT:    [[C:%.*]] = freeze i1 [[A]]
-; CHECK-NEXT:    [[D:%.*]] = and i1 [[B]], [[C]]
-; CHECK-NEXT:    ret i1 [[D]]
+; CHECK-NEXT:    ret i1 [[B]]
 ;
   %b = freeze i1 %a
   %c = freeze i1 %a
@@ -17,10 +15,9 @@ define i1 @f(i1 %a) {
 define void @f_multipleuses(i1 %a) {
 ; CHECK-LABEL: @f_multipleuses(
 ; CHECK-NEXT:    [[B:%.*]] = freeze i1 [[A:%.*]]
-; CHECK-NEXT:    [[C:%.*]] = freeze i1 [[A]]
 ; CHECK-NEXT:    call void @use1(i1 [[B]])
-; CHECK-NEXT:    call void @use1(i1 [[C]])
-; CHECK-NEXT:    call void @use1(i1 [[C]])
+; CHECK-NEXT:    call void @use1(i1 [[B]])
+; CHECK-NEXT:    call void @use1(i1 [[B]])
 ; CHECK-NEXT:    ret void
 ;
   %b = freeze i1 %a