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Treat clobber operands like early clobbers: if we have

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any, we force sdisel to do all regalloc for an asm.  This
leads to gross but correct codegen.

This fixes the rest of PR2078.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47454 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-02-21 19:43:13 +00:00
parent 1d5e8196c0
commit 0fe71e9bb1
2 changed files with 27 additions and 2 deletions
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16
lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
View File

@ -3467,6 +3467,17 @@ void AsmOperandInfo::ComputeConstraintToUse(const TargetLowering &TLI) {
}
/// GetRegistersForValue - Assign registers (virtual or physical) for the
/// specified operand. We prefer to assign virtual registers, to allow the
/// register allocator handle the assignment process. However, if the asm uses
/// features that we can't model on machineinstrs, we have SDISel do the
/// allocation. This produces generally horrible, but correct, code.
///
/// OpInfo describes the operand.
/// HasEarlyClobber is true if there are any early clobber constraints (=&r)
/// or any explicitly clobbered registers.
/// Input and OutputRegs are the set of already allocated physical registers.
///
void SelectionDAGLowering::
GetRegistersForValue(AsmOperandInfo &OpInfo, bool HasEarlyClobber,
std::set<unsigned> &OutputRegs,
@ -3723,6 +3734,11 @@ void SelectionDAGLowering::visitInlineAsm(CallSite CS) {
// Keep track of whether we see an earlyclobber.
SawEarlyClobber |= OpInfo.isEarlyClobber;
// If we see a clobber of a register, it is an early clobber.
if (OpInfo.Type == InlineAsm::isClobber &&
OpInfo.ConstraintType == TargetLowering::C_Register)
SawEarlyClobber = true;
// If this is a memory input, and if the operand is not indirect, do what we
// need to to provide an address for the memory input.
if (OpInfo.ConstraintType == TargetLowering::C_Memory &&

13
test/CodeGen/X86/2008-02-20-InlineAsmClobber.ll
View File

@ -1,4 +1,5 @@
; RUN: llvm-as < %s | llc | grep {%ecx %ecx}
; RUN: llvm-as < %s | llc | grep {a: %ecx %ecx}
; RUN: llvm-as < %s | llc | grep {b: %ecx %edx %ecx}
; PR2078
; The clobber list says that "ax" is clobbered. Make sure that eax isn't
; allocated to the input/output register.
@ -9,7 +10,15 @@ target triple = "i386-apple-darwin8"
define void @test() nounwind {
entry:
%tmp = load i32* @pixels, align 4 ; <i32> [#uses=1]
%tmp1 = tail call i32 asm sideeffect "$0 $1", "=r,0,~{dirflag},~{fpsr},~{flags},~{ax}"( i32 %tmp ) nounwind ; <i32> [#uses=1]
%tmp1 = tail call i32 asm sideeffect "a: $0 $1", "=r,0,~{dirflag},~{fpsr},~{flags},~{ax}"( i32 %tmp ) nounwind ; <i32> [#uses=1]
store i32 %tmp1, i32* @pixels, align 4
ret void
}
define void @test2(i16* %block, i8* %pixels, i32 %line_size) nounwind {
entry:
%tmp1 = getelementptr i16* %block, i32 64 ; <i16*> [#uses=1]
%tmp3 = tail call i8* asm sideeffect "b: $0 $1 $2", "=r,r,0,~{dirflag},~{fpsr},~{flags},~{ax}"( i16* %tmp1, i8* %pixels ) nounwind ; <i8*> [#uses=0]
ret void
}