This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]
Other format:	[Raw text]

[PATCH PR34114/2]Prove no-overflow for loop with NE_EXPR exit condition and non-ONE step

From: Bin Cheng <Bin dot Cheng at arm dot com>
To: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
Cc: nd <nd at arm dot com>
Date: Fri, 29 Jul 2016 15:35:50 +0000
Subject: [PATCH PR34114/2]Prove no-overflow for loop with NE_EXPR exit condition and non-ONE step
Authentication-results: sourceware.org; auth=none
Nodisclaimer: True
Spamdiagnosticmetadata: NSPM
Spamdiagnosticoutput: 1:99

Hi,
This patch fixes PR34114.  It proves no-overflow for loops with NE_EXPR exit condition and non-ONE step.  The patch contains detailed comment about when a loop like (IV=base; IV != FINAL; IV += step) doesn't overflow.

Bootstrap and test on x86_64 and AArch64.  Is it OK?

Thanks,
bin

2016-07-27  Bin Cheng  <bin.cheng@arm.com>

	PR tree-optimization/34114
	* tree-ssa-loop-niter.c (number_of_iterations_ne): Prove no-overflow
	information for more control IVs.

gcc/testsuite/ChangeLog
2016-07-27  Bin Cheng  <bin.cheng@arm.com>

	PR tree-optimization/34114
	* gcc.dg/tree-ssa/loop-42.c: New test.

Attachment: pr34114-20160724.txt
Description: pr34114-20160724.txt

Follow-Ups:
- Re: [PATCH PR34114/2]Prove no-overflow for loop with NE_EXPR exit condition and non-ONE step
  - From: Jeff Law

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]