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[ARM] Don't generate deprecated T1 STM.

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This prevents generating stm r1!, {r0, r1} on Thumb1, where value
stored for r1 is UNKONWN.

Patch by Zhaoshi Zheng.

Differential Revision: https://reviews.llvm.org/D27910



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@296538 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eli Friedman 2017-02-28 23:32:55 +00:00
parent b45bb28e1f
commit a918957b28
2 changed files with 22 additions and 4 deletions
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7
lib/Target/ARM/ARMLoadStoreOptimizer.cpp
View File

@ -609,13 +609,12 @@ MachineInstr *ARMLoadStoreOpt::CreateLoadStoreMulti(
// Exception: If the base register is in the input reglist, Thumb1 LDM is
// non-writeback.
// It's also not possible to merge an STR of the base register in Thumb1.
if (isThumb1 && isi32Load(Opcode) && ContainsReg(Regs, Base)) {
if (isThumb1 && ContainsReg(Regs, Base)) {
assert(Base != ARM::SP && "Thumb1 does not allow SP in register list");
if (Opcode == ARM::tLDRi) {
if (Opcode == ARM::tLDRi)
Writeback = false;
} else if (Opcode == ARM::tSTRi) {
else if (Opcode == ARM::tSTRi)
return nullptr;
}
}
ARM_AM::AMSubMode Mode = ARM_AM::ia;

19
test/CodeGen/Thumb/stm-deprecated.ll Normal file
View File

@ -0,0 +1,19 @@
; RUN: llc -mtriple=thumbv6m-eabi -verify-machineinstrs %s -o - | FileCheck %s
; RUN: llc -mtriple=thumbv5e-linux-gnueabi -verify-machineinstrs %s -o - | FileCheck %s
%0 = type { %0*, %0*, i32 }
@x1 = external global %0, align 4
@x2 = external global %0, align 4
; CHECK: str r0, [r1]
; CHECK-NEXT: str r1, [r1, #4]
; CHECK-NOT: stm
define void @foo(i32 %unused, %0* %x) {
%first = getelementptr inbounds %0, %0* %x, i32 0, i32 0
%second = getelementptr inbounds %0, %0* %x, i32 0, i32 1
store %0* @x1, %0** %first
store %0* %x, %0** %second
unreachable
}