[llvm] r223679 - InstSimplify: Try to bring back the rest of r223583

[David Majnemer]

Author: majnemer
Date: Mon Dec  8 12:30:43 2014
New Revision: 223679

URL: http://llvm.org/viewvc/llvm-project?rev=223679&view=rev
Log:
InstSimplify: Try to bring back the rest of r223583

This reverts r223624 with a small tweak, hopefully this will make stage3
equivalent.

Modified:
    llvm/trunk/lib/Analysis/InstructionSimplify.cpp
    llvm/trunk/test/Transforms/InstSimplify/AndOrXor.ll

Modified: llvm/trunk/lib/Analysis/InstructionSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InstructionSimplify.cpp?rev=223679&r1=223678&r2=223679&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/InstructionSimplify.cpp (original)
+++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp Mon Dec  8 12:30:43 2014
@@ -1448,8 +1448,8 @@ static Value *simplifyUnsignedRangeCheck
   Value *X, *Y;
 
   ICmpInst::Predicate EqPred;
-  if (!match(ZeroICmp, m_ICmp(EqPred, m_Value(Y), m_Zero())) &&
-      ICmpInst::isEquality(EqPred))
+  if (!match(ZeroICmp, m_ICmp(EqPred, m_Value(Y), m_Zero())) ||
+      !ICmpInst::isEquality(EqPred))
     return nullptr;
 
   ICmpInst::Predicate UnsignedPred;
@@ -1476,6 +1476,11 @@ static Value *simplifyUnsignedRangeCheck
     return UnsignedICmp;
   }
 
+  // X < Y && Y == 0  -->  false
+  if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_EQ &&
+      IsAnd)
+    return getFalse(UnsignedICmp->getType());
+
   return nullptr;
 }
 

Modified: llvm/trunk/test/Transforms/InstSimplify/AndOrXor.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/AndOrXor.ll?rev=223679&r1=223678&r2=223679&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstSimplify/AndOrXor.ll (original)
+++ llvm/trunk/test/Transforms/InstSimplify/AndOrXor.ll Mon Dec  8 12:30:43 2014
@@ -166,6 +166,15 @@ define i1 @and_icmp1(i32 %x, i32 %y) {
 ; CHECK: %[[cmp:.*]] = icmp ult i32 %x, %y
 ; CHECK: ret i1 %[[cmp]]
 
+define i1 @and_icmp2(i32 %x, i32 %y) {
+  %1 = icmp ult i32 %x, %y
+  %2 = icmp eq i32 %y, 0
+  %3 = and i1 %1, %2
+  ret i1 %3
+}
+; CHECK-LABEL: @and_icmp2(
+; CHECK: ret i1 false
+
 define i1 @or_icmp1(i32 %x, i32 %y) {
   %1 = icmp ult i32 %x, %y
   %2 = icmp ne i32 %y, 0