[llvm] r277731 - [InstCombine] use m_APInt to allow icmp eq (sub C1, X), C2 folds for splat constant vectors

[Sanjay Patel via llvm-commits]

Author: spatel
Date: Thu Aug  4 10:19:25 2016
New Revision: 277731

URL: http://llvm.org/viewvc/llvm-project?rev=277731&view=rev
Log:
[InstCombine] use m_APInt to allow icmp eq (sub C1, X), C2 folds for splat constant vectors

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=277731&r1=277730&r2=277731&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Thu Aug  4 10:19:25 2016
@@ -2265,11 +2265,11 @@ Instruction *InstCombiner::foldICmpEqual
     break;
   case Instruction::Sub:
     if (BO->hasOneUse()) {
-      // FIXME: Vectors are excluded by ConstantInt.
-      if (ConstantInt *BOp0C = dyn_cast<ConstantInt>(BOp0)) {
+      const APInt *BOC;
+      if (match(BOp0, m_APInt(BOC))) {
         // Replace ((sub A, B) != C) with (B != A-C) if A & C are constants.
-        return new ICmpInst(ICI.getPredicate(), BOp1,
-                            ConstantExpr::getSub(BOp0C, RHS));
+        Constant *SubC = ConstantExpr::getSub(cast<Constant>(BOp0), RHS);
+        return new ICmpInst(ICI.getPredicate(), BOp1, SubC);
       } else if (*RHSV == 0) {
         // Replace ((sub A, B) != 0) with (A != B)
         return new ICmpInst(ICI.getPredicate(), BOp0, BOp1);

Modified: llvm/trunk/test/Transforms/InstCombine/icmp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/icmp.ll?rev=277731&r1=277730&r2=277731&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/icmp.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/icmp.ll Thu Aug  4 10:19:25 2016
@@ -660,11 +660,9 @@ define i1 @test55(i32 %a) {
   ret i1 %cmp
 }
 
-; FIXME: Vectors should fold the same way.
 define <2 x i1> @test55vec(<2 x i32> %a) {
 ; CHECK-LABEL: @test55vec(
-; CHECK-NEXT:    [[SUB:%.*]] = sub <2 x i32> zeroinitializer, %a
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq <2 x i32> [[SUB]], <i32 123, i32 123>
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq <2 x i32> %a, <i32 -123, i32 -123>
 ; CHECK-NEXT:    ret <2 x i1> [[CMP]]
 ;
   %sub = sub <2 x i32> zeroinitializer, %a
@@ -682,11 +680,9 @@ define i1 @test56(i32 %a) {
   ret i1 %cmp
 }
 
-; FIXME: Vectors should fold the same way.
 define <2 x i1> @test56vec(<2 x i32> %a) {
 ; CHECK-LABEL: @test56vec(
-; CHECK-NEXT:    [[SUB:%.*]] = sub <2 x i32> <i32 10, i32 10>, %a
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq <2 x i32> [[SUB]], <i32 123, i32 123>
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq <2 x i32> %a, <i32 -113, i32 -113>
 ; CHECK-NEXT:    ret <2 x i1> [[CMP]]
 ;
   %sub = sub <2 x i32> <i32 10, i32 10>, %a