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ab5c703fdb
state. Previously Thumb2 would restore sp from fp like this: mov sp, r7 sub, sp, #4 If an interrupt is taken after the 'mov' but before the 'sub', callee-saved registers might be clobbered by the interrupt handler. Instead, try restoring directly from sp: add sp, #4 Or, if necessary (with VLA, etc.) use a scratch register to compute sp and then restore it: sub.w r4, r7, #8 mov sp, r7 rdar://8465407 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119977 91177308-0d34-0410-b5e6-96231b3b80d8
35 lines
644 B
LLVM
35 lines
644 B
LLVM
; rdar://8465407
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; RUN: llc < %s -mtriple=thumbv7-apple-darwin | FileCheck %s
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%struct.buf = type opaque
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declare void @bar() nounwind optsize
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define void @foo() nounwind optsize {
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; CHECK: foo:
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; CHECK: push
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; CHECK: add r7, sp, #4
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; CHECK: sub sp, #4
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entry:
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%m.i = alloca %struct.buf*, align 4
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br label %bb
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bb:
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br i1 undef, label %bb3, label %bb2
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bb2:
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call void @bar() nounwind optsize
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br i1 undef, label %bb, label %bb3
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bb3:
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br i1 undef, label %return, label %bb
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return:
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; CHECK: %return
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; 'mov sp, r7' would have left sp in an invalid state
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; CHECK-NOT: mov sp, r7
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; CHECK-NOT: sub, sp, #4
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; CHECK: add sp, #4
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ret void
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}
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