[llvm-commits] [llvm] r144123 - in /llvm/trunk: lib/Target/ARM/ARMLoadStoreOptimizer.cpp test/CodeGen/ARM/ldrd.ll

[Eli Friedman]

On Tue, Nov 8, 2011 at 1:21 PM, Evan Cheng <evan.cheng at apple.com> wrote:
> Author: evancheng
> Date: Tue Nov  8 15:21:09 2011
> New Revision: 144123
>
> URL: http://llvm.org/viewvc/llvm-project?rev=144123&view=rev
> Log:
> Add workaround for Cortex-M3 errata 602117 by replacing ldrd x, y, [x] with ldm or ldr pairs.
>
> Modified:
>    llvm/trunk/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
>    llvm/trunk/test/CodeGen/ARM/ldrd.ll
>
> Modified: llvm/trunk/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMLoadStoreOptimizer.cpp?rev=144123&r1=144122&r2=144123&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/ARM/ARMLoadStoreOptimizer.cpp (original)
> +++ llvm/trunk/lib/Target/ARM/ARMLoadStoreOptimizer.cpp Tue Nov  8 15:21:09 2011
> @@ -62,6 +62,7 @@
>
>     const TargetInstrInfo *TII;
>     const TargetRegisterInfo *TRI;
> +    const ARMSubtarget *STI;
>     ARMFunctionInfo *AFI;
>     RegScavenger *RS;
>     bool isThumb2;
> @@ -1071,11 +1072,17 @@
>   unsigned Opcode = MI->getOpcode();
>   if (Opcode == ARM::LDRD || Opcode == ARM::STRD ||
>       Opcode == ARM::t2LDRDi8 || Opcode == ARM::t2STRDi8) {
> +    const MachineOperand &BaseOp = MI->getOperand(2);
> +    unsigned BaseReg = BaseOp.getReg();
>     unsigned EvenReg = MI->getOperand(0).getReg();
>     unsigned OddReg  = MI->getOperand(1).getReg();
>     unsigned EvenRegNum = TRI->getDwarfRegNum(EvenReg, false);
>     unsigned OddRegNum  = TRI->getDwarfRegNum(OddReg, false);
> -    if ((EvenRegNum & 1) == 0 && (EvenRegNum + 1) == OddRegNum)
> +    // ARM errata 602117: LDRD with base in list may result in incorrect base
> +    // register when interrupted or faulted.
> +    bool Errata602117 = EvenReg == BaseReg && STI->getCPUString() == "cortex-m3";

Err, checking getCPUString() seems like a hack; shouldn't this be a
subtarget feature?

-Eli