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llvm-project/llvm/test/CodeGen/Thumb2/2010-11-22-EpilogueBug.ll

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Fix epilogue codegen to avoid leaving the stack pointer in an invalid 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 llvm-svn: 119977
2010-11-23 02:12:04 +08:00
; rdar://8465407
ARM & AArch64: make use of common cmpxchg idioms after expansion The C and C++ semantics for compare_exchange require it to return a bool indicating success. This gets mapped to LLVM IR which follows each cmpxchg with an icmp of the value loaded against the desired value. When lowered to ldxr/stxr loops, this extra comparison is redundant: its results are implicit in the control-flow of the function. This commit makes two changes: it replaces that icmp with appropriate PHI nodes, and then makes sure earlyCSE is called after expansion to actually make use of the opportunities revealed. I've also added -{arm,aarch64}-enable-atomic-tidy options, so that existing fragile tests aren't perturbed too much by the change. Many of them either rely on undef/unreachable too pervasively to be restored to something well-defined (particularly while making sure they test the same obscure assert from many years ago), or depend on a particular CFG shape, which is disrupted by SimplifyCFG. rdar://problem/16227836 llvm-svn: 209883
2014-05-30 18:09:59 +08:00
; RUN: llc < %s -mtriple=thumbv7-apple-ios -arm-atomic-cfg-tidy=0 | FileCheck %s
Fix epilogue codegen to avoid leaving the stack pointer in an invalid 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 llvm-svn: 119977
2010-11-23 02:12:04 +08:00
%struct.buf = type opaque
declare void @bar() nounwind optsize
[ARM] Generate consistent frame records for Thumb2 There is not an official documented ABI for frame pointers in Thumb2, but we should try to emit something which is useful. We use r7 as the frame pointer for Thumb code, which currently means that if a function needs to save a high register (r8-r11), it will get pushed to the stack between the frame pointer (r7) and link register (r14). This means that while a stack unwinder can follow the chain of frame pointers up the stack, it cannot know the offset to lr, so does not know which functions correspond to the stack frames. To fix this, we need to push the callee-saved registers in two batches, with the first push saving the low registers, fp and lr, and the second push saving the high registers. This is already implemented, but previously only used for iOS. This patch turns it on for all Thumb2 targets when frame pointers are required by the ABI, and the frame pointer is r7 (Windows uses r11, so this isn't a problem there). If frame pointer elimination is enabled we still emit a single push/pop even if we need a frame pointer for other reasons, to avoid increasing code size. We must also ensure that lr is pushed to the stack when using a frame pointer, so that we end up with a complete frame record. Situations that could cause this were rare, because we already push lr in most situations so that we can return using the pop instruction. Differential Revision: https://reviews.llvm.org/D23516 llvm-svn: 279506
2016-08-23 17:19:22 +08:00
define void @foo() nounwind optsize "no-frame-pointer-elim"="true" {
Mass update to CodeGen tests to use CHECK-LABEL for labels corresponding to function definitions for more informative error messages. No functionality change and all updated tests passed locally. This update was done with the following bash script: find test/CodeGen -name "*.ll" | \ while read NAME; do echo "$NAME" if ! grep -q "^; *RUN: *llc.*debug" $NAME; then TEMP=`mktemp -t temp` cp $NAME $TEMP sed -n "s/^define [^@]*@\([A-Za-z0-9_]*\)(.*$/\1/p" < $NAME | \ while read FUNC; do sed -i '' "s/;\(.*\)\([A-Za-z0-9_-]*\):\( *\)$FUNC: *\$/;\1\2-LABEL:\3$FUNC:/g" $TEMP done sed -i '' "s/;\(.*\)-LABEL-LABEL:/;\1-LABEL:/" $TEMP sed -i '' "s/;\(.*\)-NEXT-LABEL:/;\1-NEXT:/" $TEMP sed -i '' "s/;\(.*\)-NOT-LABEL:/;\1-NOT:/" $TEMP sed -i '' "s/;\(.*\)-DAG-LABEL:/;\1-DAG:/" $TEMP mv $TEMP $NAME fi done llvm-svn: 186280
2013-07-14 14:24:09 +08:00
; CHECK-LABEL: foo:
Fix epilogue codegen to avoid leaving the stack pointer in an invalid 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 llvm-svn: 119977
2010-11-23 02:12:04 +08:00
; CHECK: push
Roll r127459 back in: Optimize trivial branches in CodeGenPrepare, which often get created from the lowering of objectsize intrinsics. Unfortunately, a number of tests were relying on llc not optimizing trivial branches, so I had to add an option to allow them to continue to test what they originally tested. This fixes <rdar://problem/8785296> and <rdar://problem/9112893>. llvm-svn: 127498
2011-03-12 05:52:04 +08:00
; CHECK: mov r7, sp
Fix epilogue codegen to avoid leaving the stack pointer in an invalid 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 llvm-svn: 119977
2010-11-23 02:12:04 +08:00
; CHECK: sub sp, #4
entry:
%m.i = alloca %struct.buf*, align 4
br label %bb
bb:
br i1 undef, label %bb3, label %bb2
bb2:
call void @bar() nounwind optsize
br i1 undef, label %bb, label %bb3
bb3:
br i1 undef, label %return, label %bb
return:
; CHECK: %return
; 'mov sp, r7' would have left sp in an invalid state
; CHECK-NOT: mov sp, r7
; CHECK-NOT: sub, sp, #4
; CHECK: add sp, #4
ret void
}