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From: "jiwang at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/62173] [5.0 regression] [AArch64] Can't ivopt array base address while ARM can
Date: Thu, 27 Nov 2014 09:35:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62173

Jiong Wang <jiwang at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rguenth at gcc dot gnu.org
         Depends on|                            |52563

--- Comment #12 from Jiong Wang <jiwang at gcc dot gnu.org> ---
the root cause why it's not ivopted on AArch64 is because

  must_check_src_overflow = TYPE_PRECISION (ct) < TYPE_PRECISION (type);

code above in convert_affine_scev, the input type is sizetype, so DI for 64bit
arch, SI for 32bit arch, ct is SI, thus, must_check_src_overflow set to true
for 64bit arch, then failed later scev_probably_wraps_p check.

And I found similar issue reported back in 2012, at bug 52563.

I verified this bug exist on other 64 archs, like mips64, ppc64, x86-64

Richard, on 52563, I see you was working on this, do you have any thoughts on
this?