http://llvm.org/bugs/show_bug.cgi?id=18136
Bug ID: 18136
Summary: [ARM Backend]Rewinding to first LDR/VLDRD should use
reverse_iterator when emitting epiloge
Product: new-bugs
Version: unspecified
Hardware: PC
OS: Linux
Status: NEW
Severity: normal
Priority: P
Component: new bugs
Assignee: [email protected]
Reporter: [email protected]
CC: [email protected], [email protected]
Classification: Unclassified
Given an MBB like this, currently LLVM stops at t2LDMIA_RET.
(gdb) call MBB.dump()
BB#52: derived from LLVM BB %return
Predecessors according to CFG: BB#0 BB#51
%SP<def,tied1> = VLDMDIA_UPD %SP<tied0>, pred:14, pred:%noreg, %D8<def>,
%D9<def>, %D10<def>, %D11<def>, %D12<def>
%SP<def,tied1> = t2LDMIA_RET %SP<tied0>, pred:14, pred:%noreg, %R4<def>,
%R5<def>, %R6<def>, %R7<def>, %R8<def>, %R9<def>, %R10<def>, %R11<def>,
%PC<def>
lib/Target/ARM/ARMFrameLowering.cpp:385
// Unwind MBBI to point to first LDR / VLDRD.
const uint16_t *CSRegs = RegInfo->getCalleeSavedRegs(&MF);
if (MBBI != MBB.begin()) {
do {
if (isPopOpcode(MBBI->getOpcode()))
FirstPop = MBBI;
--MBBI;
} while (MBBI != MBB.begin() && isCSRestore(MBBI, TII, CSRegs));
if (!isCSRestore(MBBI, TII, CSRegs))
++MBBI;
}
With MinSize attribute (-Oz), folding SP update into pop results in misaligned
register values stored in stack.
> aa6: b001 add sp, #4
> aa8: ecbd 8b0a vpop {d8-d12}
> aac: e8bd 8ff0 ldmia.w sp!, {r4, r5, r6, r7, r8, r9, sl, fp,
> pc}
becomes:
> a9e: ecbd 8b0a vpop {d8-d12}
> aa2: e8bd 8ff8 ldmia.w sp!, {r3, r4, r5, r6, r7, r8, r9, sl,
> fp, pc}
Related bug: http://llvm.org/bugs/show_bug.cgi?id=18081
--
You are receiving this mail because:
You are on the CC list for the bug.
_______________________________________________
LLVMbugs mailing list
[email protected]
http://lists.cs.uiuc.edu/mailman/listinfo/llvmbugs
