Merging r233409:

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r233409 | ahmed.bougacha | 2015-03-27 16:28:30 -0400 (Fri, 27 Mar 2015) | 7 lines

[CodeGen] Don't attempt a tail-call with implicit sret.

Tailcalls are only OK with forwarded sret pointers. With sret demotion,
they're not, as we'd have a pointer into a soon-to-be-dead stack frame.

Differential Revison: http://reviews.llvm.org/D8510

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_36@236066 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Tom Stellard committed 2015-04-29 00:41:53 +00:00
1 parent 0eb257dd01
commit 09eef44756
2 files changed
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@@ -7353,6 +7353,10 @@ TargetLowering::LowerCallTo(TargetLowering::CallLoweringInfo &CLI) const {
Entry.Alignment = Align;
CLI.getArgs().insert(CLI.getArgs().begin(), Entry);
CLI.RetTy = Type::getVoidTy(CLI.RetTy->getContext());
// sret demotion isn't compatible with tail-calls, since the sret argument
// points into the callers stack frame.
CLI.IsTailCall = false;
} else {
for (unsigned I = 0, E = RetTys.size(); I != E; ++I) {
EVT VT = RetTys[I];
@@ -0,0 +1,46 @@
; RUN: llc < %s -mtriple arm64-apple-darwin -aarch64-load-store-opt=false -asm-verbose=false | FileCheck %s
; Disable the load/store optimizer to avoid having LDP/STPs and simplify checks.
target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
; Check that we don't try to tail-call with an sret-demoted return.
declare i1024 @test_sret() #0
; CHECK-LABEL: _test_call_sret:
; CHECK: mov x[[CALLERX8NUM:[0-9]+]], x8
; CHECK: mov x8, sp
; CHECK-NEXT: bl _test_sret
; CHECK-NEXT: ldr [[CALLERSRET1:x[0-9]+]], [sp]
; CHECK: str [[CALLERSRET1:x[0-9]+]], [x[[CALLERX8NUM]]]
; CHECK: ret
define i1024 @test_call_sret() #0 {
%a = call i1024 @test_sret()
ret i1024 %a
}
; CHECK-LABEL: _test_tailcall_sret:
; CHECK: mov x[[CALLERX8NUM:[0-9]+]], x8
; CHECK: mov x8, sp
; CHECK-NEXT: bl _test_sret
; CHECK-NEXT: ldr [[CALLERSRET1:x[0-9]+]], [sp]
; CHECK: str [[CALLERSRET1:x[0-9]+]], [x[[CALLERX8NUM]]]
; CHECK: ret
define i1024 @test_tailcall_sret() #0 {
%a = tail call i1024 @test_sret()
ret i1024 %a
}
; CHECK-LABEL: _test_indirect_tailcall_sret:
; CHECK: mov x[[CALLERX8NUM:[0-9]+]], x8
; CHECK: mov x8, sp
; CHECK-NEXT: blr x0
; CHECK-NEXT: ldr [[CALLERSRET1:x[0-9]+]], [sp]
; CHECK: str [[CALLERSRET1:x[0-9]+]], [x[[CALLERX8NUM]]]
; CHECK: ret
define i1024 @test_indirect_tailcall_sret(i1024 ()* %f) #0 {
%a = tail call i1024 %f()
ret i1024 %a
}
attributes #0 = { nounwind }