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Change TargetData's algorithm for computing defualt vector type 

alignment to match what's used in clang and GCC for __alignof, rather
than trying to guess what Legalize is going to be doing.

llvm-svn: 102206
This commit is contained in:
Dan Gohman 2010-04-23 19:41:15 +00:00
parent e3883874c5
commit e1931fa676
2 changed files with 14 additions and 19 deletions
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27
llvm/lib/Target/TargetData.cpp
View File

@ -269,18 +269,8 @@ unsigned TargetData::getAlignmentInfo(AlignTypeEnum AlignType,
return ABIInfo ? Alignments[i].ABIAlign : Alignments[i].PrefAlign;
// The best match so far depends on what we're looking for.
if (AlignType == VECTOR_ALIGN && Alignments[i].AlignType == VECTOR_ALIGN) {
// If this is a specification for a smaller vector type, we will fall back
// to it. This happens because <128 x double> can be implemented in terms
// of 64 <2 x double>.
if (Alignments[i].TypeBitWidth < BitWidth) {
// Verify that we pick the biggest of the fallbacks.
if (BestMatchIdx == -1 ||
Alignments[BestMatchIdx].TypeBitWidth < Alignments[i].TypeBitWidth)
BestMatchIdx = i;
}
} else if (AlignType == INTEGER_ALIGN &&
Alignments[i].AlignType == INTEGER_ALIGN) {
if (AlignType == INTEGER_ALIGN &&
Alignments[i].AlignType == INTEGER_ALIGN) {
// The "best match" for integers is the smallest size that is larger than
// the BitWidth requested.
if (Alignments[i].TypeBitWidth > BitWidth && (BestMatchIdx == -1 ||
@ -303,10 +293,15 @@ unsigned TargetData::getAlignmentInfo(AlignTypeEnum AlignType,
} else {
assert(AlignType == VECTOR_ALIGN && "Unknown alignment type!");
// If we didn't find a vector size that is smaller or equal to this type,
// then we will end up scalarizing this to its element type. Just return
// the alignment of the element.
return getAlignment(cast<VectorType>(Ty)->getElementType(), ABIInfo);
// By default, use natural alignment for vector types. This is consistent
// with what clang and llvm-gcc do.
unsigned Align = getTypeAllocSize(cast<VectorType>(Ty)->getElementType());
Align *= cast<VectorType>(Ty)->getNumElements();
// If the alignment is not a power of 2, round up to the next power of 2.
// This happens for non-power-of-2 length vectors.
if (Align & (Align-1))
Align = llvm::NextPowerOf2(Align);
return Align;
}
}

6
llvm/test/CodeGen/X86/widen_load-2.ll
View File

@ -24,10 +24,10 @@ define void @add3i32_2(%i32vec3* sret %ret, %i32vec3* %ap, %i32vec3* %bp) {
; CHECK: paddd
; CHECK: pextrd
; CHECK: movq
%a = load %i32vec3* %ap
%b = load %i32vec3* %bp
%a = load %i32vec3* %ap, align 8
%b = load %i32vec3* %bp, align 8
%x = add %i32vec3 %a, %b
store %i32vec3 %x, %i32vec3* %ret
store %i32vec3 %x, %i32vec3* %ret, align 8
ret void
}