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| author | Tim Northover <tnorthover@apple.com> | 2014-01-14 22:53:28 +0000 |
|---|---|---|
| committer | Tim Northover <tnorthover@apple.com> | 2014-01-14 22:53:28 +0000 |
| commit | 196c8e5fbb71098e2910e038b78f2938e3e832ff (patch) | |
| tree | dc7512dd6c75bfe306286d65d69e7241db48777b | |
| parent | 4e1247b836546287d2db40575a8daaca31351e86 (diff) | |
| download | llvm-196c8e5fbb71098e2910e038b78f2938e3e832ff.tar.gz llvm-196c8e5fbb71098e2910e038b78f2938e3e832ff.tar.bz2 llvm-196c8e5fbb71098e2910e038b78f2938e3e832ff.tar.xz | |
ARM: correctly determine final tBX_LR in Thumb1 functions
The changes caused by folding an sp-adjustment into a "pop" previously
disrupted the forward search for the final real instruction in a
terminating block. This switches to a backward search (skipping debug
instrs).
This fixes PR18399.
Patch by Zhaoshi.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199266 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Target/ARM/Thumb1FrameLowering.cpp | 6 | ||||
| -rw-r--r-- | test/CodeGen/ARM/fold-stack-adjust.ll | 23 |
2 files changed, 26 insertions, 3 deletions
diff --git a/lib/Target/ARM/Thumb1FrameLowering.cpp b/lib/Target/ARM/Thumb1FrameLowering.cpp index d8546dac31..2a587dd25b 100644 --- a/lib/Target/ARM/Thumb1FrameLowering.cpp +++ b/lib/Target/ARM/Thumb1FrameLowering.cpp @@ -304,9 +304,9 @@ void Thumb1FrameLowering::emitEpilogue(MachineFunction &MF, // we need to update the SP after popping the value. Therefore, we // pop the old LR into R3 as a temporary. - // Move back past the callee-saved register restoration - while (MBBI != MBB.end() && isCSRestore(MBBI, CSRegs)) - ++MBBI; + // Get the last instruction, tBX_RET + MBBI = MBB.getLastNonDebugInstr(); + assert (MBBI->getOpcode() == ARM::tBX_RET); // Epilogue for vararg functions: pop LR to R3 and branch off it. AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tPOP))) .addReg(ARM::R3, RegState::Define); diff --git a/test/CodeGen/ARM/fold-stack-adjust.ll b/test/CodeGen/ARM/fold-stack-adjust.ll index 81d94d16c1..feac793f4f 100644 --- a/test/CodeGen/ARM/fold-stack-adjust.ll +++ b/test/CodeGen/ARM/fold-stack-adjust.ll @@ -162,3 +162,26 @@ end: ; the correct edge-case (first inst in block is correct one to adjust). ret void } + +define void @test_varsize(...) minsize { +; CHECK-T1-LABEL: test_varsize: +; CHECK-T1: sub sp, #16 +; CHECK-T1: push {r2, r3, r4, r5, r7, lr} +; ... +; CHECK-T1: pop {r2, r3, r4, r5, r7} +; CHECK-T1: pop {r3} +; CHECK-T1: add sp, #16 +; CHECK-T1: bx r3 + +; CHECK-LABEL: test_varsize: +; CHECK: sub sp, #16 +; CHECK: push {r5, r6, r7, lr} +; ... +; CHECK: pop.w {r2, r3, r7, lr} +; CHECK: add sp, #16 +; CHECK: bx lr + + %var = alloca i8, i32 8 + call void @bar(i8* %var) + ret void +} |