From bd9e8a1faf8d718b2370710be7c67259cc14329e Mon Sep 17 00:00:00 2001
From: Sanjay Patel <spatel@rotateright.com>
Date: Thu, 4 Aug 2016 15:19:25 +0000
Subject: [PATCH] [InstCombine] use m_APInt to allow icmp eq (sub C1, X), C2
 folds for splat constant vectors

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277731 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/InstCombine/InstCombineCompares.cpp | 8 ++++----
 test/Transforms/InstCombine/icmp.ll                | 8 ++------
 2 files changed, 6 insertions(+), 10 deletions(-)

diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 6a798f91759..4dc1bb0f83c 100644
--- a/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -2265,11 +2265,11 @@ Instruction *InstCombiner::foldICmpEqualityWithConstant(ICmpInst &ICI) {
     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);
diff --git a/test/Transforms/InstCombine/icmp.ll b/test/Transforms/InstCombine/icmp.ll
index 1e1957558ad..fda911ee507 100644
--- a/test/Transforms/InstCombine/icmp.ll
+++ b/test/Transforms/InstCombine/icmp.ll
@@ -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
-- 
2.11.0