[llvm] r299847 - [InstCombine] Support folding of add instructions with vector constants into select operations

[Craig Topper via llvm-commits]

Author: ctopper
Date: Mon Apr 10 11:40:00 2017
New Revision: 299847

URL: http://llvm.org/viewvc/llvm-project?rev=299847&view=rev
Log:
[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


Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp
    llvm/trunk/test/Transforms/InstCombine/add.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp?rev=299847&r1=299846&r2=299847&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp Mon Apr 10 11:40:00 2017
@@ -1128,8 +1128,8 @@ Instruction *InstCombiner::visitAdd(Bina
     }
   }
 
-  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(Bina
         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

Modified: llvm/trunk/test/Transforms/InstCombine/add.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/add.ll?rev=299847&r1=299846&r2=299847&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/add.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/add.ll Mon Apr 10 11:40:00 2017
@@ -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>