[llvm] r267153 - [EarlyCSE] Don't add the overflow flags to the hash

[David Majnemer via llvm-commits]

Author: majnemer
Date: Fri Apr 22 09:12:50 2016
New Revision: 267153

URL: http://llvm.org/viewvc/llvm-project?rev=267153&view=rev
Log:
[EarlyCSE] Don't add the overflow flags to the hash

We take the intersection of overflow flags while CSE'ing.
This permits us to consider two instructions with different overflow
behavior to be replaceable.

Modified:
    llvm/trunk/lib/Transforms/Scalar/EarlyCSE.cpp
    llvm/trunk/test/Transforms/EarlyCSE/basic.ll

Modified: llvm/trunk/lib/Transforms/Scalar/EarlyCSE.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/EarlyCSE.cpp?rev=267153&r1=267152&r2=267153&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/EarlyCSE.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/EarlyCSE.cpp Fri Apr 22 09:12:50 2016
@@ -97,15 +97,6 @@ unsigned DenseMapInfo<SimpleValue>::getH
     if (BinOp->isCommutative() && BinOp->getOperand(0) > BinOp->getOperand(1))
       std::swap(LHS, RHS);
 
-    if (isa<OverflowingBinaryOperator>(BinOp)) {
-      // Hash the overflow behavior
-      unsigned Overflow =
-          BinOp->hasNoSignedWrap() * OverflowingBinaryOperator::NoSignedWrap |
-          BinOp->hasNoUnsignedWrap() *
-              OverflowingBinaryOperator::NoUnsignedWrap;
-      return hash_combine(BinOp->getOpcode(), Overflow, LHS, RHS);
-    }
-
     return hash_combine(BinOp->getOpcode(), LHS, RHS);
   }
 

Modified: llvm/trunk/test/Transforms/EarlyCSE/basic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/EarlyCSE/basic.ll?rev=267153&r1=267152&r2=267153&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/EarlyCSE/basic.ll (original)
+++ llvm/trunk/test/Transforms/EarlyCSE/basic.ll Fri Apr 22 09:12:50 2016
@@ -26,10 +26,9 @@ define void @test1(i8 %V, i32 *%P) {
   ; CHECK-NEXT: store volatile i32 %E
   ; CHECK-NEXT: store volatile i32 %E
 
-  %G = add nuw i32 %C, %C         ;; not a CSE with E
+  %G = add nuw i32 %C, %C
   store volatile i32 %G, i32* %P
-  ; CHECK-NEXT: %G = add nuw i32 %C, %C
-  ; CHECK-NEXT: store volatile i32 %G
+  ; CHECK-NEXT: store volatile i32 %E
   ret void
 }