[llvm] r301594 - [InstCombine] fix matcher to bind to specific operand (PR32830)

Sanjay Patel via llvm-commits llvm-commits at lists.llvm.org
Thu Apr 27 14:55:03 PDT 2017


Author: spatel
Date: Thu Apr 27 16:55:03 2017
New Revision: 301594

URL: http://llvm.org/viewvc/llvm-project?rev=301594&view=rev
Log:
[InstCombine] fix matcher to bind to specific operand (PR32830)

Matching any random value would be very wrong:
https://bugs.llvm.org/show_bug.cgi?id=32830

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
    llvm/trunk/test/Transforms/InstCombine/and-or-not.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp?rev=301594&r1=301593&r2=301594&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp Thu Apr 27 16:55:03 2017
@@ -1213,7 +1213,7 @@ static Instruction *foldAndToXor(BinaryO
   // (~B | A) & (~A | B) --> ~(A ^ B)
   // (~B | A) & (B | ~A) --> ~(A ^ B)
   if (match(Op0, m_c_Or(m_Value(A), m_Not(m_Value(B)))) &&
-      match(Op1, m_c_Or(m_Not(m_Specific(A)), m_Value(B))))
+      match(Op1, m_c_Or(m_Not(m_Specific(A)), m_Specific(B))))
     return BinaryOperator::CreateNot(Builder.CreateXor(A, B));
 
   return nullptr;

Modified: llvm/trunk/test/Transforms/InstCombine/and-or-not.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/and-or-not.ll?rev=301594&r1=301593&r2=301594&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/and-or-not.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/and-or-not.ll Thu Apr 27 16:55:03 2017
@@ -524,3 +524,23 @@ define <4 x i32> @demorgan_plus_and_to_x
   ret <4 x i32> %not
 }
 
+; https://bugs.llvm.org/show_bug.cgi?id=32830
+; Make sure we're matching operands correctly and not folding things wrongly.
+
+define i64 @PR32830(i64 %a, i64 %b, i64 %c) {
+; CHECK-LABEL: @PR32830(
+; CHECK-NEXT:    [[NOTA:%.*]] = xor i64 %a, -1
+; CHECK-NEXT:    [[NOTB:%.*]] = xor i64 %b, -1
+; CHECK-NEXT:    [[OR1:%.*]] = or i64 [[NOTB]], %a
+; CHECK-NEXT:    [[OR2:%.*]] = or i64 [[NOTA]], %c
+; CHECK-NEXT:    [[AND:%.*]] = and i64 [[OR1]], [[OR2]]
+; CHECK-NEXT:    ret i64 [[AND]]
+;
+  %nota = xor i64 %a, -1
+  %notb = xor i64 %b, -1
+  %or1 = or i64 %notb, %a
+  %or2 = or i64 %nota, %c
+  %and = and i64 %or1, %or2
+  ret i64 %and
+}
+




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