[PATCH] D39417: InstCombine: Preserve nuw when reassociating nuw ops [1/3]

[Matt Arsenault via Phabricator via llvm-commits]

arsenm updated this revision to Diff 205463.
arsenm marked an inline comment as done.
arsenm retitled this revision from "InstCombine: Preserve nuw when reassociating nuw ops" to "InstCombine: Preserve nuw when reassociating nuw ops [1/3]".

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D39417/new/

https://reviews.llvm.org/D39417

Files:
  lib/Transforms/InstCombine/InstructionCombining.cpp
  test/Transforms/InstCombine/reassociate-nuw.ll


Index: test/Transforms/InstCombine/reassociate-nuw.ll
===================================================================
--- test/Transforms/InstCombine/reassociate-nuw.ll
+++ test/Transforms/InstCombine/reassociate-nuw.ll
@@ -92,7 +92,7 @@
 
 define i32 @tryFactorization_add_nuw_mul_nuw(i32 %x) {
 ; CHECK-LABEL: @tryFactorization_add_nuw_mul_nuw(
-; CHECK-NEXT:    [[ADD2:%.*]] = shl i32 [[X:%.*]], 2
+; CHECK-NEXT:    [[ADD2:%.*]] = shl nuw i32 [[X:%.*]], 2
 ; CHECK-NEXT:    ret i32 [[ADD2]]
 ;
   %mul1 = mul nuw i32 %x, 3
@@ -102,7 +102,7 @@
 
 define i32 @tryFactorization_add_nuw_mul_nuw_int_max(i32 %x) {
 ; CHECK-LABEL: @tryFactorization_add_nuw_mul_nuw_int_max(
-; CHECK-NEXT:    [[ADD2:%.*]] = shl i32 [[X:%.*]], 31
+; CHECK-NEXT:    [[ADD2:%.*]] = shl nuw i32 [[X:%.*]], 31
 ; CHECK-NEXT:    ret i32 [[ADD2]]
 ;
   %mul1 = mul nuw i32 %x, 2147483647
Index: lib/Transforms/InstCombine/InstructionCombining.cpp
===================================================================
--- lib/Transforms/InstCombine/InstructionCombining.cpp
+++ lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -596,14 +596,21 @@
     if (BinaryOperator *BO = dyn_cast<BinaryOperator>(SimplifiedInst)) {
       if (isa<OverflowingBinaryOperator>(SimplifiedInst)) {
         bool HasNSW = false;
-        if (isa<OverflowingBinaryOperator>(&I))
+        bool HasNUW = false;
+        if (isa<OverflowingBinaryOperator>(&I)) {
           HasNSW = I.hasNoSignedWrap();
+          HasNUW = I.hasNoUnsignedWrap();
+        }
 
-        if (auto *LOBO = dyn_cast<OverflowingBinaryOperator>(LHS))
+        if (auto *LOBO = dyn_cast<OverflowingBinaryOperator>(LHS)) {
           HasNSW &= LOBO->hasNoSignedWrap();
+          HasNUW &= LOBO->hasNoUnsignedWrap();
+        }
 
-        if (auto *ROBO = dyn_cast<OverflowingBinaryOperator>(RHS))
+        if (auto *ROBO = dyn_cast<OverflowingBinaryOperator>(RHS)) {
           HasNSW &= ROBO->hasNoSignedWrap();
+          HasNUW &= ROBO->hasNoUnsignedWrap();
+        }
 
         // We can propagate 'nsw' if we know that
         //  %Y = mul nsw i16 %X, C
@@ -615,8 +622,11 @@
         const APInt *CInt;
         if (TopLevelOpcode == Instruction::Add &&
             InnerOpcode == Instruction::Mul)
-          if (match(V, m_APInt(CInt)) && !CInt->isMinSignedValue())
-            BO->setHasNoSignedWrap(HasNSW);
+          if (match(V, m_APInt(CInt))) {
+            if (!CInt->isMinSignedValue())
+              BO->setHasNoSignedWrap(HasNSW);
+            BO->setHasNoUnsignedWrap(HasNUW);
+          }
       }
     }
   }


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