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ARM: honour -f{no-,}optimize-sibling-calls

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Use the options in the ARMISelLowering to control whether tail calls are
optimised or not.  Previously, this option was entirely ignored on the ARM
target and only honoured on x86.

This option is mostly useful in profiling scenarios.  The default remains that
tail call optimisations will be applied.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203577 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Saleem Abdulrasool 2014-03-11 15:09:54 +00:00
parent 2b42ff6fdb
commit 90d0ed297f
2 changed files with 25 additions and 2 deletions
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6
lib/Target/ARM/ARMISelLowering.cpp
View File

@ -1439,9 +1439,11 @@ ARMTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
bool isStructRet = (Outs.empty()) ? false : Outs[0].Flags.isSRet();
bool isThisReturn = false;
bool isSibCall = false;
// Disable tail calls if they're not supported.
if (!Subtarget->supportsTailCall())
if (!Subtarget->supportsTailCall() || MF.getTarget().Options.DisableTailCalls)
isTailCall = false;
if (isTailCall) {
// Check if it's really possible to do a tail call.
isTailCall = IsEligibleForTailCallOptimization(Callee, CallConv,
@ -2273,7 +2275,7 @@ bool ARMTargetLowering::mayBeEmittedAsTailCall(CallInst *CI) const {
if (!Subtarget->supportsTailCall())
return false;
if (!CI->isTailCall())
if (!CI->isTailCall() || getTargetMachine().Options.DisableTailCalls)
return false;
return !Subtarget->isThumb1Only();

21
test/CodeGen/ARM/tail-call.ll Normal file
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@ -0,0 +1,21 @@
; RUN: llc -mtriple armv7 -O0 -o - < %s | FileCheck %s -check-prefix CHECK-TAIL
; RUN: llc -mtriple armv7 -O0 -disable-tail-calls -o - < %s \
; RUN: | FileCheck %s -check-prefix CHECK-NO-TAIL
declare i32 @callee(i32 %i)
define i32 @caller(i32 %i) {
entry:
%r = tail call i32 @callee(i32 %i)
ret i32 %r
}
; CHECK-LABEL: caller
; CHECK-TAIL: b callee
; CHECK-LABEL: caller
; CHECK-NO-TAIL: push {lr}
; CHECK-NO-TAIL: bl callee
; CHECK-NO-TAIL: pop {lr}
; CHECK-NO-TAIL: bx lr