[llvm] r341971 - [InstCombine] Fix incorrect usage of getPrimitiveSizeInBits when we should be using the element size for vectors

[Craig Topper via llvm-commits]

Author: ctopper
Date: Tue Sep 11 10:57:20 2018
New Revision: 341971

URL: http://llvm.org/viewvc/llvm-project?rev=341971&view=rev
Log:
[InstCombine] Fix incorrect usage of getPrimitiveSizeInBits when we should be using the element size for vectors

For vectors, getPrimitiveSizeInBits returns the full vector width. This code should using the element size for vectors. This could be fixed by calling getScalarSizeInBits, but its even easier to just get it from the APInt we're checking.

Differential Revision: https://reviews.llvm.org/D51938

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
    llvm/trunk/test/Transforms/InstCombine/mul.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp?rev=341971&r1=341970&r2=341971&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp Tue Sep 11 10:57:20 2018
@@ -171,14 +171,13 @@ Instruction *InstCombiner::visitMul(Bina
     if (match(&I, m_Mul(m_Value(NewOp), m_Constant(C1)))) {
       // Replace X*(2^C) with X << C, where C is either a scalar or a vector.
       if (Constant *NewCst = getLogBase2(NewOp->getType(), C1)) {
-        unsigned Width = NewCst->getType()->getPrimitiveSizeInBits();
         BinaryOperator *Shl = BinaryOperator::CreateShl(NewOp, NewCst);
 
         if (I.hasNoUnsignedWrap())
           Shl->setHasNoUnsignedWrap();
         if (I.hasNoSignedWrap()) {
           const APInt *V;
-          if (match(NewCst, m_APInt(V)) && *V != Width - 1)
+          if (match(NewCst, m_APInt(V)) && *V != V->getBitWidth() - 1)
             Shl->setHasNoSignedWrap();
         }
 

Modified: llvm/trunk/test/Transforms/InstCombine/mul.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/mul.ll?rev=341971&r1=341970&r2=341971&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/mul.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/mul.ll Tue Sep 11 10:57:20 2018
@@ -409,7 +409,7 @@ define i32 @test32(i32 %X) {
 
 define <2 x i32> @test32vec(<2 x i32> %X) {
 ; CHECK-LABEL: @test32vec(
-; CHECK-NEXT:    [[MUL:%.*]] = shl nsw <2 x i32> [[X:%.*]], <i32 31, i32 31>
+; CHECK-NEXT:    [[MUL:%.*]] = shl <2 x i32> [[X:%.*]], <i32 31, i32 31>
 ; CHECK-NEXT:    ret <2 x i32> [[MUL]]
 ;
   %mul = mul nsw <2 x i32> %X, <i32 -2147483648, i32 -2147483648>