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Allow trivial sibcall of vararg callee when no arguments are being passed.

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llvm-svn: 99598
This commit is contained in:
Evan Cheng 2010-03-26 02:13:13 +00:00
parent 1f419ac4da
commit 377bb993d8
4 changed files with 40 additions and 8 deletions
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5
lib/Target/X86/X86ISelLowering.cpp
View File

@ -2301,8 +2301,9 @@ X86TargetLowering::IsEligibleForTailCallOptimization(SDValue Callee,
// Look for obvious safe cases to perform tail call optimization that does not
// requite ABI changes. This is what gcc calls sibcall.
// Do not sibcall optimize vararg calls for now.
if (isVarArg)
// Do not sibcall optimize vararg calls unless the call site is not passing any
// arguments.
if (isVarArg && !Outs.empty())
return false;
// Also avoid sibcall optimization if either caller or callee uses struct

8
test/CodeGen/X86/pic.ll
View File

@ -194,10 +194,10 @@ bb12:
; LINUX: .LJTI8_0:
; LINUX: .long .LBB8_2@GOTOFF
; LINUX: .long .LBB8_2@GOTOFF
; LINUX: .long .LBB8_7@GOTOFF
; LINUX: .long .LBB8_3@GOTOFF
; LINUX: .long .LBB8_7@GOTOFF
; LINUX: .long .LBB8_8@GOTOFF
; LINUX: .long .LBB8_14@GOTOFF
; LINUX: .long .LBB8_9@GOTOFF
; LINUX: .long .LBB8_10@GOTOFF
}
declare void @foo1(...)

31
test/CodeGen/X86/sibcall.ll
View File

@ -271,3 +271,34 @@ entry:
}
declare double @bar4()
; rdar://6283267
define void @t17() nounwind ssp {
entry:
; 32: t17:
; 32: jmp {{_?}}bar5
; 64: t17:
; 64: xorb %al, %al
; 64: jmp {{_?}}bar5
tail call void (...)* @bar5() nounwind
ret void
}
declare void @bar5(...)
; rdar://7774847
define void @t18() nounwind ssp {
entry:
; 32: t18:
; 32: call {{_?}}bar6
; 32: fstp %st(0)
; 64: t18:
; 64: xorb %al, %al
; 64: jmp {{_?}}bar6
%0 = tail call double (...)* @bar6() nounwind
ret void
}
declare double @bar6(...)

4
test/CodeGen/X86/xor-icmp.ll
View File

@ -43,7 +43,7 @@ define i32 @t2(i32 %x, i32 %y) nounwind ssp {
; X32: cmpl
; X32: sete
; X32-NOT: xor
; X32: je
; X32: jne
; X64: t2:
; X64: testl
@ -51,7 +51,7 @@ define i32 @t2(i32 %x, i32 %y) nounwind ssp {
; X64: testl
; X64: sete
; X64-NOT: xor
; X64: je
; X64: jne
entry:
%0 = icmp eq i32 %x, 0 ; <i1> [#uses=1]
%1 = icmp eq i32 %y, 0 ; <i1> [#uses=1]