a01a921004
For tail-calls we want to re-use the caller stack-frame and potentially
need to copy stack arguments.
For large stack arguments, such as by-val structs, this can lead to
overwriting incoming stack arguments when preparing outgoing ones by
copying them. E.g., in cases like
%"struct.s1" = type { [19 x i32] }
define void @f0(ptr byval(%"struct.s1") %0, ptr %1) {
tail call void @f1(ptr %1, ptr byval(%"struct.s1") %0)
ret void
}
declare void @f1(ptr, ptr)
that swap arguments, the last bytes of %0 are on the stack, followed by
%1. To prepare the outgoing arguments, %0 needs to be copied and %1
needs to be loaded into r0. However, currently the copy of %0
overwrites the location of %1, resulting in loading garbage into r0.
We fix that by forcing the load to the pointer stack argument to happen
before the copy.
70 lines
2.2 KiB
LLVM
70 lines
2.2 KiB
LLVM
; RUN: llc -mtriple thumbv7em-apple-darwin -o - < %s | FileCheck %s
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%"struct.s1" = type { [19 x i32] }
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define void @f0(ptr byval(%"struct.s1") %0, ptr %1) #1 {
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; CHECK-LABEL: _f0: @ @f0
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; CHECK-NEXT: @ %bb.0:
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; CHECK-NEXT: sub sp, #16
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; CHECK-NEXT: push {r4, lr}
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; CHECK-NEXT: sub sp, #76
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; CHECK-NEXT: add.w r9, sp, #84
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; CHECK-NEXT: stm.w r9, {r0, r1, r2, r3}
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; CHECK-NEXT: mov r0, sp
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; CHECK-NEXT: add r1, sp, #84
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; CHECK-NEXT: movs r2, #76
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; CHECK-NEXT: mov r3, r0
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; CHECK-NEXT: LBB0_1: @ =>This Inner Loop Header: Depth=1
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; CHECK-NEXT: ldr r4, [r1], #4
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; CHECK-NEXT: subs r2, #4
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; CHECK-NEXT: str r4, [r3], #4
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; CHECK-NEXT: bne LBB0_1
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; CHECK-NEXT: @ %bb.2:
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; CHECK-NEXT: add.w r1, r0, #12
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; CHECK-NEXT: add r2, sp, #100
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; CHECK-NEXT: ldr r0, [sp, #160]
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; CHECK-NEXT: ldr r3, [r1], #4
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; CHECK-NEXT: str r3, [r2], #4
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; CHECK-NEXT: ldr r3, [r1], #4
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; CHECK-NEXT: str r3, [r2], #4
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; CHECK-NEXT: ldr r3, [r1], #4
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; CHECK-NEXT: str r3, [r2], #4
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; CHECK-NEXT: ldr r3, [r1], #4
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; CHECK-NEXT: str r3, [r2], #4
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; CHECK-NEXT: ldr r3, [r1], #4
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; CHECK-NEXT: str r3, [r2], #4
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; CHECK-NEXT: ldr r3, [r1], #4
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; CHECK-NEXT: str r3, [r2], #4
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; CHECK-NEXT: ldr r3, [r1], #4
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; CHECK-NEXT: str r3, [r2], #4
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; CHECK-NEXT: ldr r3, [r1], #4
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; CHECK-NEXT: str r3, [r2], #4
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; CHECK-NEXT: ldr r3, [r1], #4
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; CHECK-NEXT: str r3, [r2], #4
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; CHECK-NEXT: ldr r3, [r1], #4
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; CHECK-NEXT: str r3, [r2], #4
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; CHECK-NEXT: ldr r3, [r1], #4
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; CHECK-NEXT: str r3, [r2], #4
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; CHECK-NEXT: ldr r3, [r1], #4
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; CHECK-NEXT: str r3, [r2], #4
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; CHECK-NEXT: ldr r3, [r1], #4
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; CHECK-NEXT: str r3, [r2], #4
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; CHECK-NEXT: ldr r3, [r1], #4
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; CHECK-NEXT: str r3, [r2], #4
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; CHECK-NEXT: ldr r3, [r1], #4
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; CHECK-NEXT: str r3, [r2], #4
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; CHECK-NEXT: ldr r3, [r1], #4
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; CHECK-NEXT: str r3, [r2], #4
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; CHECK-NEXT: ldm.w sp, {r1, r2, r3}
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; CHECK-NEXT: add sp, #76
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; CHECK-NEXT: pop.w {r4, lr}
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; CHECK-NEXT: add sp, #16
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; CHECK-NEXT: b.w _f1
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tail call void @f1(ptr %1, ptr byval(%"struct.s1") %0)
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ret void
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}
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declare void @f1(ptr, ptr)
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attributes #1 = { nounwind "frame-pointes"="non-leaf" }
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