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[Bug rtl-optimization/81020] [6/7/8 Regression] wrong code with -O -fno-tree-bit-ccp -fno-tree-coalesce-vars -fno-tree-vrp
- From: "ktkachov at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Wed, 06 Dec 2017 11:43:02 +0000
- Subject: [Bug rtl-optimization/81020] [6/7/8 Regression] wrong code with -O -fno-tree-bit-ccp -fno-tree-coalesce-vars -fno-tree-vrp
- Auto-submitted: auto-generated
- References: <bug-81020-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81020
--- Comment #11 from ktkachov at gcc dot gnu.org ---
(In reply to Richard Biener from comment #10)
> There's nothing wrong with the GIMPLE (looked at aarch64) so it must be some
> other RTL optimization issue.
>
> aarch64 assembler is
>
> foo:
> adrp x1, .LANCHOR0
> ldr w1, [x1, #:lo12:.LANCHOR0]
> orr w0, w1, w0
> ret
>
> that looks indeed bogus (just does return v | x;?)
Indeed, bisection points to the combine.c commit at r255384