From 4ed87e3dc1fcc1fe6146e58d539bd6fd86b3ed16 Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper@gmail.com>
Date: Mon, 10 Apr 2017 16:40:00 +0000
Subject: [PATCH] [InstCombine] Support folding of add instructions with vector
 constants into select operations

We currently only fold scalar add of constants into selects. This improves this to support vectors too.

Differential Revision: https://reviews.llvm.org/D31683



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299847 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/InstCombine/InstCombineAddSub.cpp | 9 ++-------
 test/Transforms/InstCombine/add.ll               | 9 +++------
 2 files changed, 5 insertions(+), 13 deletions(-)

diff --git a/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index c946c096821..65f72d0fb55 100644
--- a/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -1128,8 +1128,8 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
     }
   }
 
-  if (isa<Constant>(RHS) && isa<PHINode>(LHS))
-    if (Instruction *NV = FoldOpIntoPhi(I))
+  if (isa<Constant>(RHS))
+    if (Instruction *NV = foldOpWithConstantIntoOperand(I))
       return NV;
 
   if (I.getType()->getScalarType()->isIntegerTy(1))
@@ -1200,11 +1200,6 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
         return BinaryOperator::CreateAnd(NewAdd, C2);
       }
     }
-
-    // Try to fold constant add into select arguments.
-    if (SelectInst *SI = dyn_cast<SelectInst>(LHS))
-      if (Instruction *R = FoldOpIntoSelect(I, SI))
-        return R;
   }
 
   // add (select X 0 (sub n A)) A  -->  select X A n
diff --git a/test/Transforms/InstCombine/add.ll b/test/Transforms/InstCombine/add.ll
index 84a48ece63f..648305d134c 100644
--- a/test/Transforms/InstCombine/add.ll
+++ b/test/Transforms/InstCombine/add.ll
@@ -272,8 +272,7 @@ define i32 @test19(i1 %C) {
 
 define <2 x i32> @test19vec(i1 %C) {
 ; CHECK-LABEL: @test19vec(
-; CHECK-NEXT:    [[A:%.*]] = select i1 [[C:%.*]], <2 x i32> <i32 1000, i32 1000>, <2 x i32> <i32 10, i32 10>
-; CHECK-NEXT:    [[V:%.*]] = add nuw nsw <2 x i32> [[A]], <i32 123, i32 123>
+; CHECK-NEXT:    [[V:%.*]] = select i1 [[C:%.*]], <2 x i32> <i32 1123, i32 1123>, <2 x i32> <i32 133, i32 133>
 ; CHECK-NEXT:    ret <2 x i32> [[V]]
 ;
   %A = select i1 %C, <2 x i32> <i32 1000, i32 1000>, <2 x i32> <i32 10, i32 10>
@@ -604,8 +603,7 @@ define i32 @test42(i1 %C) {
 
 define <2 x i32> @test42vec(i1 %C) {
 ; CHECK-LABEL: @test42vec(
-; CHECK-NEXT:    [[A:%.*]] = select i1 [[C:%.*]], <2 x i32> <i32 1000, i32 1000>, <2 x i32> <i32 10, i32 10>
-; CHECK-NEXT:    [[V:%.*]] = add nuw nsw <2 x i32> [[A]], <i32 123, i32 123>
+; CHECK-NEXT:    [[V:%.*]] = select i1 [[C:%.*]], <2 x i32> <i32 1123, i32 1123>, <2 x i32> <i32 133, i32 133>
 ; CHECK-NEXT:    ret <2 x i32> [[V]]
 ;
   %A = select i1 %C, <2 x i32> <i32 1000, i32 1000>, <2 x i32> <i32 10, i32 10>
@@ -615,8 +613,7 @@ define <2 x i32> @test42vec(i1 %C) {
 
 define <2 x i32> @test42vec2(i1 %C) {
 ; CHECK-LABEL: @test42vec2(
-; CHECK-NEXT:    [[A:%.*]] = select i1 [[C:%.*]], <2 x i32> <i32 1000, i32 2500>, <2 x i32> <i32 10, i32 30>
-; CHECK-NEXT:    [[V:%.*]] = add nuw nsw <2 x i32> [[A]], <i32 123, i32 333>
+; CHECK-NEXT:    [[V:%.*]] = select i1 [[C:%.*]], <2 x i32> <i32 1123, i32 2833>, <2 x i32> <i32 133, i32 363>
 ; CHECK-NEXT:    ret <2 x i32> [[V]]
 ;
   %A = select i1 %C, <2 x i32> <i32 1000, i32 2500>, <2 x i32> <i32 10, i32 30>
-- 
2.40.0