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Enable support for returning two long-double values in ST(0)/ST(1). 

This allows us to compile fp-stack-2results.ll into:

_test:
	fldz
	fld1
	ret

which returns 1 in ST(0) and 0 in ST(1).  This is needed for x86-64
_Complex long double.

llvm-svn: 48632
This commit is contained in:
Chris Lattner 2008-03-21 05:57:20 +00:00
parent c44160ce6e
commit b6f04a3e0a
3 changed files with 15 additions and 7 deletions
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6
llvm/lib/Target/X86/X86CallingConv.td
View File

@ -38,15 +38,15 @@ def RetCC_X86Common : CallingConv<[
CCIfType<[v8i8, v4i16, v2i32, v1i64], CCAssignToReg<[MM0]>>,
// Long double types are always returned in ST0 (even with SSE).
CCIfType<[f80], CCAssignToReg<[ST0]>>
CCIfType<[f80], CCAssignToReg<[ST0, ST1]>>
]>;
// X86-32 C return-value convention.
def RetCC_X86_32_C : CallingConv<[
// The X86-32 calling convention returns FP values in ST0, otherwise it is the
// same as the common X86 calling conv.
CCIfType<[f32], CCAssignToReg<[ST0]>>,
CCIfType<[f64], CCAssignToReg<[ST0]>>,
CCIfType<[f32], CCAssignToReg<[ST0, ST1]>>,
CCIfType<[f64], CCAssignToReg<[ST0, ST1]>>,
CCDelegateTo<RetCC_X86Common>
]>;

5
llvm/lib/Target/X86/X86FloatingPoint.cpp
View File

@ -1053,9 +1053,6 @@ void FPS::handleSpecialFP(MachineBasicBlock::iterator &I) {
return;
}
assert(0 && "TODO: This code should work, but has never been tested."
"Test it when we have multiple FP return values working");
// Otherwise, we are returning two values:
// 2) If returning the same value for both, we only have one thing in the FP
// stack. Consider: RET FP1, FP1
@ -1083,7 +1080,7 @@ void FPS::handleSpecialFP(MachineBasicBlock::iterator &I) {
/// 4) Finally, FirstFPRegOp must be in ST(0) and SecondFPRegOp must be in
/// ST(1). Just remove both from our understanding of the stack and return.
assert(getStackEntry(0) == FirstFPRegOp && "Unknown regs live");
assert(getStackEntry(0) == SecondFPRegOp && "Unknown regs live");
assert(getStackEntry(1) == SecondFPRegOp && "Unknown regs live");
StackTop = 0;
return;
}

11
llvm/test/CodeGen/X86/fp-stack-2results.ll Normal file
View File

@ -0,0 +1,11 @@
; RUN: llvm-as < %s | llc -march=x86 | grep fldz
; RUN: llvm-as < %s | llc -march=x86-64 | grep fld1
; This is basically this code on x86-64:
; _Complex long double test() { return 1.0; }
define {x86_fp80, x86_fp80} @test() {
%A = fpext double 1.0 to x86_fp80
%B = fpext double 0.0 to x86_fp80
ret x86_fp80 %A, x86_fp80 %B
}