From: Jessica Paquette Date: Fri, 6 Sep 2019 16:49:13 +0000 (+0000) Subject: [AArch64][GlobalISel] Always fall back on tail calls with -tailcallopt X-Git-Tag: llvmorg-11-init~9824 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=121d9114f5676f676095d5d6f1988abe870549c3;p=platform%2Fupstream%2Fllvm.git [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 llvm-svn: 371227 --- diff --git a/llvm/lib/Target/AArch64/AArch64CallLowering.cpp b/llvm/lib/Target/AArch64/AArch64CallLowering.cpp index e97b329..ffca0e7 100644 --- a/llvm/lib/Target/AArch64/AArch64CallLowering.cpp +++ b/llvm/lib/Target/AArch64/AArch64CallLowering.cpp @@ -567,6 +567,12 @@ bool AArch64CallLowering::lowerCall(MachineIRBuilder &MIRBuilder, 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 SplitArgs; for (auto &OrigArg : Info.OrigArgs) { splitToValueTypes(OrigArg, SplitArgs, DL, MRI, Info.CallConv); diff --git a/llvm/test/CodeGen/AArch64/tail-call.ll b/llvm/test/CodeGen/AArch64/tail-call.ll index ab63413..fe3e7d7 100644 --- a/llvm/test/CodeGen/AArch64/tail-call.ll +++ b/llvm/test/CodeGen/AArch64/tail-call.ll @@ -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 i32], i64, i64) 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()