[llvm] r279398 - [InstCombine] use m_APInt to allow icmp (shl X, Y), C folds for splat constant vectors, part 2

[Sanjay Patel via llvm-commits]

Author: spatel
Date: Sun Aug 21 11:28:22 2016
New Revision: 279398

URL: http://llvm.org/viewvc/llvm-project?rev=279398&view=rev
Log:
[InstCombine] use m_APInt to allow icmp (shl X, Y), C folds for splat constant vectors, part 2

This is a partial enablement (move the ConstantInt guard down).

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
    llvm/trunk/test/Transforms/InstCombine/icmp.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=279398&r1=279397&r2=279398&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Sun Aug 21 11:28:22 2016
@@ -2024,16 +2024,16 @@ Instruction *InstCombiner::foldICmpShlCo
     }
   }
 
-  // FIXME: This check restricts all folds under here to scalar types.
-  ConstantInt *RHS = dyn_cast<ConstantInt>(Cmp.getOperand(1));
-  if (!RHS)
-    return nullptr;
-
   // If this is a signed comparison to 0 and the shift is sign preserving,
   // use the shift LHS operand instead; isSignTest may change 'Pred', so only
   // do that if we're sure to not continue on in this function.
   if (cast<BinaryOperator>(Shl)->hasNoSignedWrap() && isSignTest(Pred, *C))
-    return new ICmpInst(Pred, X, Constant::getNullValue(RHS->getType()));
+    return new ICmpInst(Pred, X, Constant::getNullValue(X->getType()));
+
+  // FIXME: This check restricts all folds under here to scalar types.
+  ConstantInt *RHS = dyn_cast<ConstantInt>(Cmp.getOperand(1));
+  if (!RHS)
+    return nullptr;
 
   // Otherwise, if this is a comparison of the sign bit, simplify to and/test.
   bool TrueIfSigned = false;

Modified: llvm/trunk/test/Transforms/InstCombine/icmp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/icmp.ll?rev=279398&r1=279397&r2=279398&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/icmp.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/icmp.ll Sun Aug 21 11:28:22 2016
@@ -1160,11 +1160,9 @@ define i1 @icmp_shl_nsw_sge1(i32 %x) {
   ret i1 %cmp
 }
 
-; FIXME: Vectors should fold the same way.
 define <2 x i1> @icmp_shl_nsw_sge1_vec(<2 x i32> %x) {
 ; CHECK-LABEL: @icmp_shl_nsw_sge1_vec(
-; CHECK-NEXT:    [[SHL:%.*]] = shl nsw <2 x i32> %x, <i32 21, i32 21>
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt <2 x i32> [[SHL]], zeroinitializer
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt <2 x i32> %x, zeroinitializer
 ; CHECK-NEXT:    ret <2 x i1> [[CMP]]
 ;
   %shl = shl nsw <2 x i32> %x, <i32 21, i32 21>