[PATCH, asmcons] Fix PR rtl-optimization/89313: ICE in process_alt_operands, at lra-constraints.c:2962

[Jeff Law]

On 2/20/19 8:19 PM, Peter Bergner wrote:
> PR89313 exposes a bug in the asmcons pass where it replaces input operands
> with matching constraints with their associated output operands, as well as
> all other uses of its pseudo registers.  This is normally fine.  However, if
> the matched output operand is marked as early clobber, then we cannot replace
> the uses of 'input' that do not have matching constraints, since they by
> definition conflict with the early clobber output operand and could be
> clobbered if assigned to the same register as the output operand.
> 
> The patch below fixes the bug by only doing the input pseudo replacement
> if the output operand is not early clobber or the input operand is known
> to be a matching constraint.
> 
> This passed bootstrap and regression testing with no regressions on
> both x86_64-linux and powerpc64le-linux.  Ok for mainline?
> 
> Peter
> 
> 
> gcc/
> 	PR rtl-optimization/89313
> 	* function.c (matching_constraint_num): New static function.
> 	(match_asm_constraints_1): Use it.  Fixup white space and comment.
> 	Don't replace inputs with non-matching constraints which conflict
> 	with early clobber outputs.
> 
> gcc/testsuite/
> 	PR rtl-optimization/89313
> 	* gcc.dg/pr89313.c: New test.
OK.
jeff