Ping Re: [patch, ARM] ICE in get_arm_condition_code()

[Chung-Lin Tang]

Ping.

On 2011/1/26 11:09 AM, Chung-Lin Tang wrote:
> Ping.
> (I'll fix the minor nits before actually committing, thanks Ramana :)
> 
> On 2011/1/13 08:24, Chung-Lin Tang wrote:
>> Hi,
>> there's an ICE in arm.c:get_arm_condition_code(), from here:
>> https://bugs.launchpad.net/gcc-linaro/+bug/689887
>>
>> The report was on a 4.5 based compiler, but I verified it also occurs on
>> current trunk, under Thumb-2.
>>
>> The problem as I found, happens in RTL ifcvt after the combine pass.
>> ifcvt.c:noce_emit_cmove() creates this:
>> (insn 58 57 59 4 (parallel [
>>             (set (reg:CC_NCV 24 cc)
>>                 (compare:CC_NCV (reg:DI 140)
>>                     (reg:DI 147)))
>>             (clobber (scratch:SI))
>>         ]) p.c:13 202 {*arm_cmpdi_insn}
>>      (nil))
>>
>> (insn 59 58 60 4 (set (reg:SI 146)
>> 	(if_then_else:SI (gt (reg:CC_NCV 24 cc)
>>                 (const_int 0 [0]))
>>             (reg:SI 145)
>>             (reg:SI 144))) p.c:13 701 {*thumb2_movsicc_insn}
>>      (nil))
>>
>> which is wrong; the GT comparison requires testing of the Z, C, and V
>> flags, which CC_NCV does not satisfy. The ICE happens later when the asm
>> emitting actually hits assert fail in get_arm_condition_code().
>>
>> This patch fixes this by stratifying the "arm_comparison_operator"
>> predicate, by leveraging the current logic in get_arm_condition_code().
>> I abstracted out the body into a new arm_comparison_to_cond_code()
>> function, which returns an invalid code instead of assert fail, and used
>> it to add a check to the comparison RTX in "arm_comparison_operator".
>> This way, invalid comparisons like the above would be blocked from emitting.
>>
>> Tests were run with no regressions found. Okay for trunk?
>>
>> Thanks,
>> Chung-Lin
>>
>> 2011-01-12  Chung-Lin Tang  <cltang@codesourcery.com>
>>
>>         * config/arm/arm.h (enum arm_cond_code): Add ARM_COND_INVALID.
>>         * config/arm/arm.c (arm_comparison_to_cond_code): Renamed from
>>         get_arm_condition_code(), change gcc_unreachable()s to return
>>         ARM_COND_INVALID.
>>         (get_arm_condition_code): Implement by calling
>>         arm_comparison_to_cond_code(), with result test by gcc_assert().
>>         (arm_valid_comparison_p): New function to test for valid ARM
>>         comparison RTX.
>>         * config/arm/arm-protos.h (arm_valid_comparison_p): Add
>> 	prototype.
>>         * config/arm/predicates.md (arm_comparison_operator): Add
>> 	additional check based on arm_valid_comparison_p().
>>
>>         testsuite/
>>         * gcc.target/arm/20110112-1.c: New test.
>>
>>
>>
>