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[Patch AArch64] Fix for PR62262

From: Carrot Wei <carrot at google dot com>
To: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
Date: Tue, 26 Aug 2014 15:18:36 -0700
Subject: [Patch AArch64] Fix for PR62262
Authentication-results: sourceware.org; auth=none

Hi

In insn pattern "*andim_ashift<mode>_bfiz", if the operands[2] is larger than
the size of register, gcc may generate invalid assembler code. If operands[2]
is larger than the size of the underlying type of INTVAL, the following insn
condition may also be undefined.

"exact_log2 ((INTVAL (operands[3]) >> INTVAL (operands[2])) + 1) >= 0
 && (INTVAL (operands[3]) & ((1 << INTVAL (operands[2])) - 1)) == 0"

It can be fixed by checking the value of operands[2] before using it.

Passed regression test without failure. OK for trunk and 4.9 branch?

thanks
Guozhi Wei


2014-08-26  Guozhi Wei  <carrot@google.com>

        PR target/62262
        * config/aarch64/aarch64.md (*andim_ashift<mode>_bfiz): Check the shift
        amount before using it.


2014-08-26  Guozhi Wei  <carrot@google.com>

        PR target/62262
        * gcc.target/aarch64/pr62262.c: New test.

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Follow-Ups:
- Re: [Patch AArch64] Fix for PR62262
  - From: Richard Earnshaw

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