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It's possible to have a constant expression who's size is quite big (e.g.,

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i128). In that case, we may not be able to print out the MCExpr as an
expression. For instance, we could have an MCExpr like this:

    0xBEEF0000BEEF0000 | (0xBEEF0000BEEF0000 << 64)

The MCExpr printer handles sizes up to 64-bits, but this expression would
require 128-bits. In this situation, try to evaluate the constant expression and
emit that as the value into 64-bit chunks.
<rdar://problem/11070338>

llvm-svn: 153081
This commit is contained in:
Bill Wendling 2012-03-20 08:56:43 +00:00
parent 61aa773498
commit 338ddac8f7
2 changed files with 34 additions and 11 deletions
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28
lib/CodeGen/AsmPrinter/AsmPrinter.cpp
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@ -1847,13 +1847,12 @@ static void EmitGlobalConstantLargeInt(const ConstantInt *CI,
static void EmitGlobalConstantImpl(const Constant *CV, unsigned AddrSpace,
AsmPrinter &AP) {
if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) {
uint64_t Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
const TargetData *TD = AP.TM.getTargetData();
uint64_t Size = TD->getTypeAllocSize(CV->getType());
if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV))
return AP.OutStreamer.EmitZeros(Size, AddrSpace);
}
if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
switch (Size) {
case 1:
case 2:
@ -1874,7 +1873,6 @@ static void EmitGlobalConstantImpl(const Constant *CV, unsigned AddrSpace,
return EmitGlobalConstantFP(CFP, AddrSpace, AP);
if (isa<ConstantPointerNull>(CV)) {
unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
AP.OutStreamer.EmitIntValue(0, Size, AddrSpace);
return;
}
@ -1888,20 +1886,28 @@ static void EmitGlobalConstantImpl(const Constant *CV, unsigned AddrSpace,
if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
return EmitGlobalConstantStruct(CVS, AddrSpace, AP);
// Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
// vectors).
if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV))
if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
// Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
// vectors).
if (CE->getOpcode() == Instruction::BitCast)
return EmitGlobalConstantImpl(CE->getOperand(0), AddrSpace, AP);
if (Size > 8) {
// If the constant expression's size is greater than 64-bits, then we have
// to emit the value in chunks. Try to constant fold the value and emit it
// that way.
Constant *New = ConstantFoldConstantExpression(CE, TD);
if (New && New != CE)
return EmitGlobalConstantImpl(New, AddrSpace, AP);
}
}
if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
return EmitGlobalConstantVector(V, AddrSpace, AP);
// Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
// thread the streamer with EmitValue.
AP.OutStreamer.EmitValue(LowerConstant(CV, AP),
AP.TM.getTargetData()->getTypeAllocSize(CV->getType()),
AddrSpace);
AP.OutStreamer.EmitValue(LowerConstant(CV, AP), Size, AddrSpace);
}
/// EmitGlobalConstant - Print a general LLVM constant to the .s file.

17
test/CodeGen/X86/2012-03-20-LargeConstantExpr.ll Normal file
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@ -0,0 +1,17 @@
; RUN: llc < %s -mtriple=x86_64-apple-darwin | FileCheck %s
; <rdar://problem/11070338>
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.8.0"
; CHECK: _.memset_pattern:
; CHECK-NEXT: .quad 4575657222473777152
; CHECK-NEXT: .quad 4575657222473777152
@.memset_pattern = internal unnamed_addr constant i128 or (i128 zext (i64 bitcast (<2 x float> <float 1.000000e+00, float 1.000000e+00> to i64) to i128), i128 shl (i128 zext (i64 bitcast (<2 x float> <float 1.000000e+00, float 1.000000e+00> to i64) to i128), i128 64)), align 16
define void @foo(i8* %a, i64 %b) {
call void @memset_pattern16(i8* %a, i8* bitcast (i128* @.memset_pattern to i8*), i64 %b)
ret void
}
declare void @memset_pattern16(i8*, i8*, i64)