| ; RUN: llc -mtriple=hexagon-unknown--elf -hexagon-initial-cfg-cleanup=false < %s | FileCheck %s |
| ; RUN: llc -mtriple=hexagon-unknown--elf -hexagon-initial-cfg-cleanup=false -mattr=+noreturn-stack-elim < %s | FileCheck %s --check-prefix=CHECK-FLAG |
| |
| ; Test the noreturn stack elimination feature. We've added a new flag/feature |
| ; that attempts to eliminate the local stack for noreturn nounwind functions. |
| ; The optimization eliminates the need to save callee saved registers, and |
| ; eliminates the allocframe, when no local stack space is needed. |
| |
| %struct.A = type { i32, i32 } |
| |
| ; Test the case when noreturn-stack-elim determins that both callee saved |
| ; register do not need to be saved, and the allocframe can be eliminated. |
| |
| ; CHECK-LABEL: test1 |
| ; CHECK: memd(r29+#-16) = r17:16 |
| ; CHECK: allocframe |
| |
| ; CHECK-FLAG-LABEL: test1 |
| ; CHECK-FLAG-NOT: memd(r29+#-16) = r17:16 |
| ; CHECK-FLAG-NOT: allocframe |
| |
| define dso_local void @test1(i32 %a, %struct.A* %b) local_unnamed_addr #0 { |
| entry: |
| %n = getelementptr inbounds %struct.A, %struct.A* %b, i32 0, i32 0 |
| store i32 %a, i32* %n, align 4 |
| tail call void @f1() #3 |
| tail call void @nrf1(%struct.A* %b) #4 |
| unreachable |
| } |
| |
| ; Test that noreturn-stack-elim doesn't eliminate the local stack, when |
| ; a function needs to allocate a local variable. |
| |
| ; CHECK-LABEL: test2 |
| ; CHECK: allocframe |
| |
| ; CHECK-FLAG-LABEL: test2 |
| ; CHECK-FLAG: allocframe |
| |
| define dso_local void @test2() local_unnamed_addr #0 { |
| entry: |
| %a = alloca i32, align 4 |
| %0 = bitcast i32* %a to i8* |
| call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull %0) #4 |
| call void @f3(i32* nonnull %a) #4 |
| unreachable |
| } |
| |
| ; Test that noreturn-stack-elim can elimnate the allocframe when no locals |
| ; are allocated on the stack. |
| |
| ; CHECK-LABEL: test3 |
| ; CHECK: allocframe |
| |
| ; CHECK-FLAG-LABEL: test3 |
| ; CHECK-FLAG-NOT: allocframe |
| |
| define dso_local void @test3(i32 %a) local_unnamed_addr #0 { |
| entry: |
| %add = add nsw i32 %a, 5 |
| call void @f2(i32 %add) |
| unreachable |
| } |
| |
| ; Test that nothing is optimized when an alloca is needed for local stack. |
| |
| ; CHECK-LABEL: test4 |
| ; CHECK: allocframe |
| |
| ; CHECK-FLAG-LABEL: test4 |
| ; CHECK-FLAG: allocframe |
| |
| define dso_local void @test4(i32 %n) local_unnamed_addr #0 { |
| entry: |
| %vla = alloca i32, i32 %n, align 8 |
| call void @f3(i32* nonnull %vla) #4 |
| unreachable |
| } |
| |
| |
| declare dso_local void @f1() local_unnamed_addr |
| declare dso_local void @f2(i32) local_unnamed_addr |
| declare dso_local void @f3(i32*) local_unnamed_addr |
| |
| declare dso_local void @nrf1(%struct.A*) local_unnamed_addr #2 |
| |
| declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture) #5 |
| |
| attributes #0 = { noreturn nounwind } |
| attributes #2 = { noreturn } |
| attributes #3 = { nounwind } |
| attributes #4 = { noreturn nounwind } |
| attributes #5 = { argmemonly nounwind } |
| |