From a523add327c6cfdd68cf9b788ea808068d0f508c Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Wed, 27 Jan 2021 15:35:52 +0100 Subject: [PATCH] rtl-optimization/80960 - avoid creating garbage RTL in DSE The following avoids repeatedly turning VALUE RTXen into sth useful and re-applying a constant offset through get_addr via DSE check_mem_read_rtx. Instead perform this once for all stores to be visited in check_mem_read_rtx. This avoids allocating 1.6GB of garbage PLUS RTXen on the PR80960 testcase, fixing the memory usage regression from old GCC. 2021-01-27 Richard Biener PR rtl-optimization/80960 * dse.c (check_mem_read_rtx): Call get_addr on the offsetted address. --- gcc/dse.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/gcc/dse.c b/gcc/dse.c index c88587e..da0df54 100644 --- a/gcc/dse.c +++ b/gcc/dse.c @@ -2219,6 +2219,11 @@ check_mem_read_rtx (rtx *loc, bb_info_t bb_info) } if (maybe_ne (offset, 0)) mem_addr = plus_constant (get_address_mode (mem), mem_addr, offset); + /* Avoid passing VALUE RTXen as mem_addr to canon_true_dependence + which will over and over re-create proper RTL and re-apply the + offset above. See PR80960 where we almost allocate 1.6GB of PLUS + RTXen that way. */ + mem_addr = get_addr (mem_addr); if (group_id >= 0) { -- 2.7.4