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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
60 lines
2.2 KiB
LLVM
60 lines
2.2 KiB
LLVM
; RUN: llc < %s -mtriple=thumbv7-apple-darwin -mcpu=cortex-a8 -O3 | FileCheck %s
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@.str = private constant [4 x i8] c"%d\0A\00", align 4 ; <[4 x i8]*> [#uses=1]
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define internal fastcc i32 @Callee(i32 %i) nounwind {
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entry:
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; CHECK: Callee:
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; CHECK: push
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; CHECK: mov r4, sp
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; CHECK: sub.w r12, r4, #1000
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; CHECK: mov sp, r12
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%0 = icmp eq i32 %i, 0 ; <i1> [#uses=1]
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br i1 %0, label %bb2, label %bb
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bb: ; preds = %entry
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%1 = alloca [1000 x i8], align 4 ; <[1000 x i8]*> [#uses=1]
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%.sub = getelementptr inbounds [1000 x i8]* %1, i32 0, i32 0 ; <i8*> [#uses=2]
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%2 = call i32 (i8*, i32, i32, i8*, ...)* @__sprintf_chk(i8* %.sub, i32 0, i32 1000, i8* getelementptr inbounds ([4 x i8]* @.str, i32 0, i32 0), i32 %i) nounwind ; <i32> [#uses=0]
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%3 = load i8* %.sub, align 4 ; <i8> [#uses=1]
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%4 = sext i8 %3 to i32 ; <i32> [#uses=1]
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ret i32 %4
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bb2: ; preds = %entry
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; Must restore sp from fp here. Make sure not to leave sp in a temporarily invalid
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; state though. rdar://8465407
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; CHECK-NOT: mov sp, r7
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; CHECK: sub.w r4, r7, #8
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; CHECK: mov sp, r4
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; CHECK: pop
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ret i32 0
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}
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declare i32 @__sprintf_chk(i8*, i32, i32, i8*, ...) nounwind
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define i32 @main() nounwind {
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; CHECK: main:
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bb.nph:
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br label %bb
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bb: ; preds = %bb, %bb.nph
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%0 = phi i32 [ 0, %bb.nph ], [ %3, %bb ] ; <i32> [#uses=2]
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%j.01 = phi i32 [ 0, %bb.nph ], [ %2, %bb ] ; <i32> [#uses=1]
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%1 = tail call fastcc i32 @Callee(i32 %0) nounwind ; <i32> [#uses=1]
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%2 = add nsw i32 %1, %j.01 ; <i32> [#uses=2]
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%3 = add nsw i32 %0, 1 ; <i32> [#uses=2]
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%exitcond = icmp eq i32 %3, 10000 ; <i1> [#uses=1]
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br i1 %exitcond, label %bb2, label %bb
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bb2: ; preds = %bb
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; No need to restore sp from fp here.
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; CHECK: printf
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; CHECK-NOT: mov sp, r7
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; CHECK-NOT: sub sp, #12
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; CHECK: pop
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%4 = tail call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4 x i8]* @.str, i32 0, i32 0), i32 %2) nounwind ; <i32> [#uses=0]
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ret i32 0
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}
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declare i32 @printf(i8* nocapture, ...) nounwind
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