[llvm-commits] [llvm] r102509 - /llvm/trunk/lib/Target/X86/X86FloatingPoint.cpp

[Chris Lattner]

On Apr 28, 2010, at 11:28 AM, Jakob Stoklund Olesen wrote:

> Author: stoklund
> Date: Wed Apr 28 13:28:37 2010
> New Revision: 102509
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=102509&view=rev
> Log:
> Teach X86FloatingPoint that a register can be killed multiple times by the same
> instruction.
> 
> This instruction would crash the pass:
> 
>  INLINEASM <es:foo $0 $1>, 9, %FP0<kill>, 9, %FP0<kill>, 14, %EFLAGS<earlyclobber,def,dead>
> 
> Now it doesn't.

Great!  Testcase? :)

-Chris

> 
> Modified:
>    llvm/trunk/lib/Target/X86/X86FloatingPoint.cpp
> 
> Modified: llvm/trunk/lib/Target/X86/X86FloatingPoint.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86FloatingPoint.cpp?rev=102509&r1=102508&r2=102509&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86FloatingPoint.cpp (original)
> +++ llvm/trunk/lib/Target/X86/X86FloatingPoint.cpp Wed Apr 28 13:28:37 2010
> @@ -1088,8 +1088,7 @@
>     // 'f' constraint.  These should be turned into the current ST(x) register
>     // in the machine instr.  Also, any kills should be explicitly popped after
>     // the inline asm.
> -    unsigned Kills[7];
> -    unsigned NumKills = 0;
> +    unsigned Kills = 0;
>     for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
>       MachineOperand &Op = MI->getOperand(i);
>       if (!Op.isReg() || Op.getReg() < X86::FP0 || Op.getReg() > X86::FP6)
> @@ -1103,7 +1102,7 @@
>       // asm.  We just remember it for now, and pop them all off at the end in
>       // a batch.
>       if (Op.isKill())
> -        Kills[NumKills++] = FPReg;
> +        Kills |= 1U << FPReg;
>     }
> 
>     // If this asm kills any FP registers (is the last use of them) we must
> @@ -1114,9 +1113,11 @@
>     // Note: this might be a non-optimal pop sequence.  We might be able to do
>     // better by trying to pop in stack order or something.
>     MachineBasicBlock::iterator InsertPt = MI;
> -    while (NumKills)
> -      freeStackSlotAfter(InsertPt, Kills[--NumKills]);
> -
> +    while (Kills) {
> +      unsigned FPReg = CountTrailingZeros_32(Kills);
> +      freeStackSlotAfter(InsertPt, FPReg);
> +      Kills &= ~(1U << FPReg);
> +    }
>     // Don't delete the inline asm!
>     return;
>   }
> 
> 
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