From 00a324e8939f724855afb3f5f159cae9e1c53e92 Mon Sep 17 00:00:00 2001
From: Sanjay Patel <spatel@rotateright.com>
Date: Wed, 3 Aug 2016 22:08:44 +0000
Subject: [PATCH] [InstCombine] use m_APInt to allow icmp eq (add X, C1), C2
 folds for splat constant vectors

llvm-svn: 277659
---
 llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp | 14 ++++++++------
 llvm/test/Transforms/InstCombine/add.ll                 |  4 +---
 llvm/test/Transforms/InstCombine/icmp.ll                |  5 +----
 3 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 576aa2d..75c4342 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -2227,13 +2227,14 @@ Instruction *InstCombiner::foldICmpEqualityWithConstant(ICmpInst &ICI) {
       }
     }
     break;
-  case Instruction::Add:
+  case Instruction::Add: {
     // Replace ((add A, B) != C) with (A != C-B) if B & C are constants.
-    // FIXME: Vectors are excluded by ConstantInt.
-    if (ConstantInt *BOp1C = dyn_cast<ConstantInt>(BOp1)) {
-      if (BO->hasOneUse())
-        return new ICmpInst(ICI.getPredicate(), BOp0,
-                            ConstantExpr::getSub(RHS, BOp1C));
+    const APInt *BOC;
+    if (match(BOp1, m_APInt(BOC))) {
+      if (BO->hasOneUse()) {
+        Constant *SubC = ConstantExpr::getSub(RHS, cast<Constant>(BOp1));
+        return new ICmpInst(ICI.getPredicate(), BOp0, SubC);
+      }
     } else if (*RHSV == 0) {
       // Replace ((add A, B) != 0) with (A != -B) if A or B is
       // efficiently invertible, or if the add has just this one use.
@@ -2248,6 +2249,7 @@ Instruction *InstCombiner::foldICmpEqualityWithConstant(ICmpInst &ICI) {
       }
     }
     break;
+  }
   case Instruction::Xor:
     if (BO->hasOneUse()) {
       if (Constant *BOC = dyn_cast<Constant>(BOp1)) {
diff --git a/llvm/test/Transforms/InstCombine/add.ll b/llvm/test/Transforms/InstCombine/add.ll
index 10c1592..7c46257 100644
--- a/llvm/test/Transforms/InstCombine/add.ll
+++ b/llvm/test/Transforms/InstCombine/add.ll
@@ -264,11 +264,9 @@ define i1 @test21(i32 %x) {
   ret i1 %y
 }
 
-; FIXME: Vectors should fold the same way.
 define <2 x i1> @test21vec(<2 x i32> %x) {
 ; CHECK-LABEL: @test21vec(
-; CHECK-NEXT:    [[T:%.*]] = add <2 x i32> %x, <i32 4, i32 4>
-; CHECK-NEXT:    [[Y:%.*]] = icmp eq <2 x i32> [[T]], <i32 123, i32 123>
+; CHECK-NEXT:    [[Y:%.*]] = icmp eq <2 x i32> %x, <i32 119, i32 119>
 ; CHECK-NEXT:    ret <2 x i1> [[Y]]
 ;
   %t = add <2 x i32> %x, <i32 4, i32 4>
diff --git a/llvm/test/Transforms/InstCombine/icmp.ll b/llvm/test/Transforms/InstCombine/icmp.ll
index cefe45c..1e19575 100644
--- a/llvm/test/Transforms/InstCombine/icmp.ll
+++ b/llvm/test/Transforms/InstCombine/icmp.ll
@@ -1004,12 +1004,9 @@ define i1 @test70(i32 %X) {
   ret i1 %C
 }
 
-; FIXME: Vectors should fold the same way.
-
 define <2 x i1> @test70vec(<2 x i32> %X) {
 ; CHECK-LABEL: @test70vec(
-; CHECK-NEXT:    [[B:%.*]] = add <2 x i32> %X, <i32 2, i32 2>
-; CHECK-NEXT:    [[C:%.*]] = icmp ne <2 x i32> [[B]], <i32 4, i32 4>
+; CHECK-NEXT:    [[C:%.*]] = icmp ne <2 x i32> %X, <i32 2, i32 2>
 ; CHECK-NEXT:    ret <2 x i1> [[C]]
 ;
   %B = add <2 x i32> %X, <i32 2, i32 2>
-- 
2.7.4