[PATCH] D134135: [InstCombine] Fix bug when folding x + (x | -x) to x & (x - 1)

[Sanjay Patel via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rGf52dd920d400: [InstCombine] Fix bug when folding x + (x | -x) to x & (x - 1) (authored by marcauberer, committed by spatel).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D134135/new/

https://reviews.llvm.org/D134135

Files:
  llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
  llvm/test/Transforms/InstCombine/add_or_sub.ll


Index: llvm/test/Transforms/InstCombine/add_or_sub.ll
===================================================================
--- llvm/test/Transforms/InstCombine/add_or_sub.ll
+++ llvm/test/Transforms/InstCombine/add_or_sub.ll
@@ -7,9 +7,7 @@
 
 define i32 @add_or_sub_comb_i32_commuted1_nuw(i32 %x) {
 ; CHECK-LABEL: @add_or_sub_comb_i32_commuted1_nuw(
-; CHECK-NEXT:    [[TMP1:%.*]] = add i32 [[X:%.*]], -1
-; CHECK-NEXT:    [[ADD:%.*]] = and i32 [[TMP1]], [[X]]
-; CHECK-NEXT:    ret i32 [[ADD]]
+; CHECK-NEXT:    ret i32 [[X:%.*]]
 ;
   %sub = sub i32 0, %x
   %or = or i32 %sub, %x
@@ -20,7 +18,9 @@
 define i8 @add_or_sub_comb_i8_commuted2_nsw(i8 %p) {
 ; CHECK-LABEL: @add_or_sub_comb_i8_commuted2_nsw(
 ; CHECK-NEXT:    [[X:%.*]] = mul i8 [[P:%.*]], [[P]]
-; CHECK-NEXT:    ret i8 [[X]]
+; CHECK-NEXT:    [[TMP1:%.*]] = add nsw i8 [[X]], -1
+; CHECK-NEXT:    [[ADD:%.*]] = and i8 [[TMP1]], [[X]]
+; CHECK-NEXT:    ret i8 [[ADD]]
 ;
   %x = mul i8 %p, %p ; thwart complexity-based canonicalization
   %sub = sub i8 0, %x
Index: llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -1404,7 +1404,7 @@
                                                       m_Deferred(A)))))) {
     Value *Add =
         Builder.CreateAdd(A, Constant::getAllOnesValue(A->getType()), "",
-                          I.hasNoSignedWrap(), I.hasNoSignedWrap());
+                          I.hasNoUnsignedWrap(), I.hasNoSignedWrap());
     return BinaryOperator::CreateAnd(Add, A);
   }
 


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