[PATCH][ARM] PR 67439: Allow matching of *arm32_movhf when -mrestrict-it is on

Kyrill Tkachov kyrylo.tkachov@arm.com
Thu Sep 10 09:03:00 GMT 2015


Hi all,

The ICE in this PR occurs when trying to compile code containing half-precision FP operations
for Thumb2 with -mrestrict-it and an -mfpu that does not support fp16 (-mfpu=neon or lower).

The problem is that we disable for -mrestrict-it the *arm32_movhf pattern that performs the move using only
the general regs.

Instead what we should do is allow the pattern to match but forbid its predication for -mrestrict-it
by using the predicable_short_it attribute.

This fixes the ICE.

Bootstrap and test on arm is ok.
This bug appears on the 5 and 4.9 branches as well.
Ok for all active branches if testing there comes clean?

Thanks,
Kyrill

2015-09-10  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>

     PR target/67439
     * config/arm/arm.md (*arm32_movhf): Remove !arm_restrict_it from
     predicate.  Set predicable_short_it attr to "no".

2015-09-10  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>

     PR target/67439
     * gcc.target/arm/pr67439_1.c: New test.
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