[Alpha PATCH] Fix gcc.c-torture/compile/20061005-1.c ICE

["Roger Sayle" <roger at eyesopen dot com>]

The following patch to the alpha backend resolves twelve unexpected
failures in the gcc testsuite on alphaev67-dec-osf5.1.  The cause of
the failures is the ICE:

testsuite/gcc.c-torture/compile/20061005-1.c: In function 'testc2':
testsuite/gcc.c-torture/compile/20061005-1.c:23: error: unrecognizable insn:
(insn 11 10 12 3 (set (reg:DI 74)
        (ashift:DI (zero_extend:DI (const_int -3 [0xfffffffffffffffd]))
            (ashift:DI (reg/f:DI 69)
                (const_int 3 [0x3])))) -1 (nil)
    (nil))
testsuite/gcc.c-torture/compile/20061005-1.c:23: internal compiler error:
in extract_insn, at recog.c:2108

This pattern is the result of the initial RTL expansion of the
__sync_val_compare_and_swap built-in, which places the constant -3 in the
above pattern, whose constraints only allow a register in that context.


I'm not familiar with the synchronization primitives of the alpha, there
may be a better insn for handling immediate constants, but the patch below
resolves these failures by tweaking alpha.c's emit_insxl to call force_reg
on the operand that needs to be in a register for these patterns.

The following patch has been tested on alphaev67-dec-osf5.1 with a full
"make bootstrap", all default languages except Java, and regression tested
with a top-level "make -k check" with no new failures.

Ok for mainline?


2007-02-08  Roger Sayle  <roger@eyesopen.com>

        * config/alpha/alpha.c (emit_insxl): Force the first operand of
        the insbl or inswl pattern into a register.

Roger
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Attachment: patcha.txt
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