45 lines
1.3 KiB
LLVM
45 lines
1.3 KiB
LLVM
; Using VLAs(Variable Length Arrays) in a function will use R6 to keep track
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; of the stack frame, and also spill/restore R6 to the stack.
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; This tests that using -ffixed-r6 (-mattr=+reserve-r6) will stop R6
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; being used and also stop it being spilled/restored to the stack.
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; RUN: llc < %s -mcpu=cortex-m0 -mtriple=thumbv7-arm-none-eabi | FileCheck %s --check-prefix=CHECK-STATIC --check-prefix=CHECK-R6
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; RUN: llc < %s -mcpu=cortex-m0 -mtriple=thumbv7-arm-none-eabi -mattr=+reserve-r6 | FileCheck %s --check-prefix=CHECK-STATIC --check-prefix=CHECK-NO-R6
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define void @f() #0 {
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entry:
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%i = alloca i32, align 4
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store i32 0, i32* %i, align 4
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%saved_stack = alloca i8*, align 4
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%0 = call i8* @llvm.stacksave()
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store i8* %0, i8** %saved_stack, align 4
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%__vla_expr0 = alloca i32, align 4
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%1 = load i32, i32* %i, align 4
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%vla = alloca double, i32 %1, align 8
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store i32 %1, i32* %__vla_expr0, align 4
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%2 = load i8*, i8** %saved_stack, align 4
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call void @llvm.stackrestore(i8* %2)
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ret void
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}
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declare i8* @llvm.stacksave() #1
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declare void @llvm.stackrestore(i8* %ptr) #1
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attributes #0 = { noinline nounwind "stackrealign" }
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attributes #1 = { nounwind }
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; CHECK-STATIC: push {r4,
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; CHECK-R6: r6
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; CHECK-NO-R6-NOT: r6
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; CHECK-STATIC: lr}
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; CHECK-R6: r6
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; CHECK-NO-R6-NOT: r6
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; CHECK-STATIC: pop {r4,
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; CHECK-R6: r6
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; CHECK-NO-R6-NOT: r6
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; CHECK-STATIC: pc}
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