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[code size][ARM] Emit regular call instructions instead of the move, branch sequence

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166854 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Quentin Colombet 2012-10-27 01:10:17 +00:00
parent 7797e8f901
commit 80acd97266
2 changed files with 42 additions and 2 deletions
lib/Target/ARM
ARMISelLowering.cpp
test/CodeGen/ARM
call-noret-forsize.ll

10
lib/Target/ARM/ARMISelLowering.cpp

@ -1594,11 +1594,15 @@ ARMTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
// FIXME: handle tail calls differently.
unsigned CallOpc;
bool HasForceSizeAttr = MF.getFunction()->getFnAttributes().
hasAttribute(Attributes::ForceSizeOpt);
if (Subtarget->isThumb()) {
if ((!isDirect || isARMFunc) && !Subtarget->hasV5TOps())
CallOpc = ARMISD::CALL_NOLINK;
else if (doesNotRet && isDirect && !isARMFunc &&
Subtarget->hasRAS() && !Subtarget->isThumb1Only())
Subtarget->hasRAS() && !Subtarget->isThumb1Only() &&
// Emit regular call when code size is the priority
!HasForceSizeAttr)
// "mov lr, pc; b _foo" to avoid confusing the RSP
CallOpc = ARMISD::CALL_NOLINK;
else
@ -1606,7 +1610,9 @@ ARMTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
} else {
if (!isDirect && !Subtarget->hasV5TOps()) {
CallOpc = ARMISD::CALL_NOLINK;
} else if (doesNotRet && isDirect && Subtarget->hasRAS())
} else if (doesNotRet && isDirect && Subtarget->hasRAS() &&
// Emit regular call when code size is the priority
!HasForceSizeAttr)
// "mov lr, pc; b _foo" to avoid confusing the RSP
CallOpc = ARMISD::CALL_NOLINK;
else

34
test/CodeGen/ARM/call-noret-forsize.ll Normal file

@ -0,0 +1,34 @@
; RUN: llc < %s -mtriple=armv7-apple-ios -mcpu=cortex-a8 | FileCheck %s -check-prefix=ARM
; RUN: llc < %s -mtriple=armv7-apple-ios -mcpu=swift | FileCheck %s -check-prefix=SWIFT
; RUN: llc < %s -mtriple=thumbv7-apple-ios -mcpu=cortex-a8 | FileCheck %s -check-prefix=T2
; rdar://12348580
define void @t1() noreturn forcesizeopt nounwind ssp {
entry:
; ARM: t1:
; ARM: bl _bar
; SWIFT: t1:
; SWIFT: bl _bar
; T2: t1:
; T2: blx _bar
tail call void @bar() noreturn nounwind
unreachable
}
define void @t2() noreturn forcesizeopt nounwind ssp {
entry:
; ARM: t2:
; ARM: bl _t1
; SWIFT: t2:
; SWIFT: bl _t1
; T2: t2:
; T2: bl _t1
tail call void @t1() noreturn nounwind
unreachable
}
declare void @bar() noreturn