From 841a5f32add8d0c9fd33454e89b67b8fa3ded0c3 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Wed, 16 Mar 2022 14:53:06 +0100 Subject: [PATCH] tree-optimization/104931 - mitigate niter analysis issue To: gcc-patches@gcc.gnu.org The following backports a pointer associating pattern from trunk that mitigates an issue with number_of_iterations_lt_to_ne in which context we fail to fold a comparison but succeed in folding a related subtraction. In the failure mode this results in a loop wrongly assumed looping with a bogus number of iterations, resulting in crashing of the premake application on start. With the backported simplification we are able to fold the comparison and correctly compute the loop as not iterating. I have failed to create a standalone testcase. I belive part of the issue is still latent but I have failed to nail down the issue exactly. Still I believe the backporting of the mitigation patch is the most sensible and safe thing at this point. 2022-03-16 Richard Biener PR tree-optimization/104931 * match.pd ((ptr) (x p+ y) p+ z -> (ptr) (x p+ (y + z))): New GENERIC simplification. --- gcc/match.pd | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/gcc/match.pd b/gcc/match.pd index 05a08d0f96a..a005dcd42bd 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -1997,6 +1997,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (simplify (pointer_plus (pointer_plus:s @0 @1) @3) (pointer_plus @0 (plus @1 @3))) +#if GENERIC +(simplify + (pointer_plus (convert:s (pointer_plus:s @0 @1)) @3) + (convert:type (pointer_plus @0 (plus @1 @3)))) +#endif /* Pattern match tem1 = (long) ptr1; -- 2.34.1