[llvm] r371227 - [AArch64][GlobalISel] Always fall back on tail calls with -tailcallopt
Jessica Paquette via llvm-commits
llvm-commits at lists.llvm.org
Fri Sep 6 09:49:13 PDT 2019
Author: paquette
Date: Fri Sep 6 09:49:13 2019
New Revision: 371227
URL: http://llvm.org/viewvc/llvm-project?rev=371227&view=rev
Log:
[AArch64][GlobalISel] Always fall back on tail calls with -tailcallopt
-tailcallopt requires that we perform different stack adjustments than with
sibling calls. For example, the `@caller_to0_from8` function in
test/CodeGen/AArch64/tail-call.ll requires that we adjust SP. Without
-tailcallopt, this adjustment does not happen. With it, however, it is expected.
So, to ensure that adding sibling call support doesn't break -tailcallopt,
make CallLowering always fall back on possible tail calls when -tailcallopt
is passed in.
Update test/CodeGen/AArch64/tail-call.ll with a GlobalISel line to make sure
that we don't differ from the SDAG implementation at any point.
Differential Revision: https://reviews.llvm.org/D67245
Modified:
llvm/trunk/lib/Target/AArch64/AArch64CallLowering.cpp
llvm/trunk/test/CodeGen/AArch64/tail-call.ll
Modified: llvm/trunk/lib/Target/AArch64/AArch64CallLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64CallLowering.cpp?rev=371227&r1=371226&r2=371227&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64CallLowering.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64CallLowering.cpp Fri Sep 6 09:49:13 2019
@@ -567,6 +567,12 @@ bool AArch64CallLowering::lowerCall(Mach
return false;
}
+ if (Info.IsTailCall && MF.getTarget().Options.GuaranteedTailCallOpt) {
+ // TODO: Until we lower all tail calls, we should fall back on this.
+ LLVM_DEBUG(dbgs() << "Cannot handle -tailcallopt yet.\n");
+ return false;
+ }
+
SmallVector<ArgInfo, 8> SplitArgs;
for (auto &OrigArg : Info.OrigArgs) {
splitToValueTypes(OrigArg, SplitArgs, DL, MRI, Info.CallConv);
Modified: llvm/trunk/test/CodeGen/AArch64/tail-call.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/tail-call.ll?rev=371227&r1=371226&r2=371227&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/tail-call.ll (original)
+++ llvm/trunk/test/CodeGen/AArch64/tail-call.ll Fri Sep 6 09:49:13 2019
@@ -1,4 +1,5 @@
-; RUN: llc -verify-machineinstrs < %s -mtriple=aarch64-none-linux-gnu -tailcallopt | FileCheck %s
+; RUN: llc -verify-machineinstrs < %s -mtriple=aarch64-none-linux-gnu -tailcallopt | FileCheck %s --check-prefixes=SDAG,COMMON
+; RUN: llc -global-isel -global-isel-abort=2 -verify-machineinstrs < %s -mtriple=aarch64-none-linux-gnu -tailcallopt | FileCheck %s --check-prefixes=GISEL,COMMON
declare fastcc void @callee_stack0()
declare fastcc void @callee_stack8([8 x i32], i64)
@@ -6,98 +7,98 @@ declare fastcc void @callee_stack16([8 x
declare extern_weak fastcc void @callee_weak()
define fastcc void @caller_to0_from0() nounwind {
-; CHECK-LABEL: caller_to0_from0:
-; CHECK-NEXT: // %bb.
+; COMMON-LABEL: caller_to0_from0:
+; COMMON-NEXT: // %bb.
tail call fastcc void @callee_stack0()
ret void
-; CHECK-NEXT: b callee_stack0
+; COMMON-NEXT: b callee_stack0
}
define fastcc void @caller_to0_from8([8 x i32], i64) {
-; CHECK-LABEL: caller_to0_from8:
+; COMMON-LABEL: caller_to0_from8:
tail call fastcc void @callee_stack0()
ret void
-; CHECK: add sp, sp, #16
-; CHECK-NEXT: b callee_stack0
+; COMMON: add sp, sp, #16
+; COMMON-NEXT: b callee_stack0
}
define fastcc void @caller_to8_from0() {
-; CHECK-LABEL: caller_to8_from0:
-; CHECK: sub sp, sp, #32
+; COMMON-LABEL: caller_to8_from0:
+; COMMON: sub sp, sp, #32
; Key point is that the "42" should go #16 below incoming stack
; pointer (we didn't have arg space to reuse).
tail call fastcc void @callee_stack8([8 x i32] undef, i64 42)
ret void
-; CHECK: str {{x[0-9]+}}, [sp, #16]!
-; CHECK-NEXT: b callee_stack8
+; COMMON: str {{x[0-9]+}}, [sp, #16]!
+; COMMON-NEXT: b callee_stack8
}
define fastcc void @caller_to8_from8([8 x i32], i64 %a) {
-; CHECK-LABEL: caller_to8_from8:
-; CHECK: sub sp, sp, #16
+; COMMON-LABEL: caller_to8_from8:
+; COMMON: sub sp, sp, #16
; Key point is that the "%a" should go where at SP on entry.
tail call fastcc void @callee_stack8([8 x i32] undef, i64 42)
ret void
-; CHECK: str {{x[0-9]+}}, [sp, #16]!
-; CHECK-NEXT: b callee_stack8
+; COMMON: str {{x[0-9]+}}, [sp, #16]!
+; COMMON-NEXT: b callee_stack8
}
define fastcc void @caller_to16_from8([8 x i32], i64 %a) {
-; CHECK-LABEL: caller_to16_from8:
-; CHECK: sub sp, sp, #16
+; COMMON-LABEL: caller_to16_from8:
+; COMMON: sub sp, sp, #16
; Important point is that the call reuses the "dead" argument space
; above %a on the stack. If it tries to go below incoming-SP then the
; callee will not deallocate the space, even in fastcc.
tail call fastcc void @callee_stack16([8 x i32] undef, i64 42, i64 2)
-; CHECK: stp {{x[0-9]+}}, {{x[0-9]+}}, [sp, #16]!
-; CHECK-NEXT: b callee_stack16
+; COMMON: stp {{x[0-9]+}}, {{x[0-9]+}}, [sp, #16]!
+; COMMON-NEXT: b callee_stack16
ret void
}
define fastcc void @caller_to8_from24([8 x i32], i64 %a, i64 %b, i64 %c) {
-; CHECK-LABEL: caller_to8_from24:
-; CHECK: sub sp, sp, #16
+; COMMON-LABEL: caller_to8_from24:
+; COMMON: sub sp, sp, #16
; Key point is that the "%a" should go where at #16 above SP on entry.
tail call fastcc void @callee_stack8([8 x i32] undef, i64 42)
ret void
-; CHECK: str {{x[0-9]+}}, [sp, #32]!
-; CHECK-NEXT: b callee_stack8
+; COMMON: str {{x[0-9]+}}, [sp, #32]!
+; COMMON-NEXT: b callee_stack8
}
define fastcc void @caller_to16_from16([8 x i32], i64 %a, i64 %b) {
-; CHECK-LABEL: caller_to16_from16:
-; CHECK: sub sp, sp, #16
+; COMMON-LABEL: caller_to16_from16:
+; COMMON: sub sp, sp, #16
; Here we want to make sure that both loads happen before the stores:
; otherwise either %a or %b will be wrongly clobbered.
tail call fastcc void @callee_stack16([8 x i32] undef, i64 %b, i64 %a)
ret void
-; CHECK: ldp {{x[0-9]+}}, {{x[0-9]+}}, [sp, #16]
-; CHECK: stp {{x[0-9]+}}, {{x[0-9]+}}, [sp, #16]!
-; CHECK-NEXT: b callee_stack16
+; COMMON: ldp {{x[0-9]+}}, {{x[0-9]+}}, [sp, #16]
+; COMMON: stp {{x[0-9]+}}, {{x[0-9]+}}, [sp, #16]!
+; COMMON-NEXT: b callee_stack16
}
; Weakly-referenced extern functions cannot be tail-called, as AAELF does
; not define the behaviour of branch instructions to undefined weak symbols.
define fastcc void @caller_weak() {
-; CHECK-LABEL: caller_weak:
-; CHECK: bl callee_weak
+; COMMON-LABEL: caller_weak:
+; COMMON: bl callee_weak
tail call void @callee_weak()
ret void
}
@@ -105,10 +106,17 @@ define fastcc void @caller_weak() {
declare { [2 x float] } @get_vec2()
define { [3 x float] } @test_add_elem() {
-; CHECK-LABEL: test_add_elem:
-; CHECK: bl get_vec2
-; CHECK: fmov s2, #1.0
-; CHECK: ret
+; SDAG-LABEL: test_add_elem:
+; SDAG: bl get_vec2
+; SDAG: fmov s2, #1.0
+; SDAG: ret
+; GISEL-LABEL: test_add_elem:
+; GISEL: fmov s8, #1.00000000
+; GISEL: bl get_vec2
+; GISEL: ldr x30, [sp, #8]
+; GISEL: mov v2.16b, v8.16b
+; GISEL: ldr d8, [sp], #16
+; GISEL: ret
%call = tail call { [2 x float] } @get_vec2()
%arr = extractvalue { [2 x float] } %call, 0
@@ -123,11 +131,11 @@ define { [3 x float] } @test_add_elem()
declare double @get_double()
define { double, [2 x double] } @test_mismatched_insert() {
-; CHECK-LABEL: test_mismatched_insert:
-; CHECK: bl get_double
-; CHECK: bl get_double
-; CHECK: bl get_double
-; CHECK: ret
+; COMMON-LABEL: test_mismatched_insert:
+; COMMON: bl get_double
+; COMMON: bl get_double
+; COMMON: bl get_double
+; COMMON: ret
%val0 = call double @get_double()
%val1 = call double @get_double()
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