Implement support for simplifying vector comparisons by 0.0 and 1.0 like we

do for scalars.  Patch contributed by Nicolas Capens

This also generalizes the previous xforms to work on long double, now that
isExactlyValue works for long double.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54653 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index eebb7cf82f53b4b0642c3b70e9f5e213cd380b9b..bdea6e40d21e2fd527d6334b8505cc129a1f3f59 100644 (file)
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -2480,10 +2480,17 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
 
       // "In IEEE floating point, x*1 is not equivalent to x for nans.  However,
       // ANSI says we can drop signals, so we can do this anyway." (from GCC)
-      // We need a better interface for long double here.
-      if (Op1->getType() == Type::FloatTy || Op1->getType() == Type::DoubleTy)
-        if (Op1F->isExactlyValue(1.0))
-          return ReplaceInstUsesWith(I, Op0);  // Eliminate 'mul double %X, 1.0'
+      if (Op1F->isExactlyValue(1.0))
+        return ReplaceInstUsesWith(I, Op0);  // Eliminate 'mul double %X, 1.0'
+    } else if (isa<VectorType>(Op1->getType())) {
+      if (isa<ConstantAggregateZero>(Op1))
+        return ReplaceInstUsesWith(I, Op1);
+      
+      // As above, vector X*splat(1.0) -> X in all defined cases.
+      if (ConstantVector *Op1V = dyn_cast<ConstantVector>(Op1))
+        if (ConstantFP *F = dyn_cast_or_null<ConstantFP>(Op1V->getSplatValue()))
+          if (F->isExactlyValue(1.0))
+            return ReplaceInstUsesWith(I, Op0);
     }
     
     if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0))
@@ -11636,3 +11643,4 @@ FunctionPass *llvm::createInstructionCombiningPass() {
   return new InstCombiner();
 }
 
+

diff --git a/test/Transforms/InstCombine/mul.ll b/test/Transforms/InstCombine/mul.ll
index 8e9ab8d4213ec1de11575c099e21d444cbf93944..1a7402543418b69f00204ac66ff128fb4b707716 100644 (file)
--- a/test/Transforms/InstCombine/mul.ll
+++ b/test/Transforms/InstCombine/mul.ll
@@ -1,7 +1,5 @@
 ; This test makes sure that mul instructions are properly eliminated.
-;
 ; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep mul
-; END.
 
 define i32 @test1(i32 %A) {
         %B = mul i32 %A, 1              ; <i32> [#uses=1]
@@ -78,3 +76,18 @@ define i32 @test12(i8 %a, i32 %b) {
         ret i32 %e
 }
 
+; PR2642
+define internal void @test13(<4 x float>*) {
+       load <4 x float>* %0, align 1
+       mul <4 x float> %2, < float 1.000000e+00, float 1.000000e+00, float 1.000000e+00, float 1.000000e+00 >
+       store <4 x float> %3, <4 x float>* %0, align 1
+       ret void
+}
+
+define internal void @test14(<4 x float>*) {
+       load <4 x float>* %0, align 1
+       mul <4 x float> %2, zeroinitializer
+       store <4 x float> %3, <4 x float>* %0, align 1
+       ret void
+}
+