mirrors/gcc
0
0
Fork 0
mirror of https://gcc.gnu.org/git/gcc.git synced 2025-01-09 04:23:46 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

tree-optimization/91403 - avoid excessive code-generation

Browse Source 
The vectorizer, for large permuted grouped loads, generates
inefficient intermediate code (cleaned up only later) that runs
into complexity issues in SCEV analysis and elsewhere.  For the
non-single-element interleaving case we already put a hard limit
in place, this applies the same limit to the missing case.

2021-01-11  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/91403
	* tree-vect-data-refs.c (vect_analyze_group_access_1): Cap
	single-element interleaving group size at 4096 elements.

	* gcc.dg/vect/pr91403.c: New testcase.
This commit is contained in:
Richard Biener 2021-01-11 12:04:32 +01:00
parent 6ebf79fcd4
commit 84684e0f78
2 changed files with 16 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
gcc/testsuite/gcc.dg/vect/pr91403.c Normal file
View File

@ -0,0 +1,11 @@
/* { dg-do compile } */
/* { dg-additional-options "-O3" } */
extern int a[][1000000];
int b;
void c()
{
for (int d = 2; d <= 9; d++)
for (int e = 32; e <= 41; e++)
b += a[d][5];
}

6
gcc/tree-vect-data-refs.c
View File

@ -2538,7 +2538,11 @@ vect_analyze_group_access_1 (vec_info *vinfo, dr_vec_info *dr_info)
size. */
if (DR_IS_READ (dr)
&& (dr_step % type_size) == 0
&& groupsize > 0)
&& groupsize > 0
/* This could be UINT_MAX but as we are generating code in a very
inefficient way we have to cap earlier.
See PR91403 for example. */
&& groupsize <= 4096)
{
DR_GROUP_FIRST_ELEMENT (stmt_info) = stmt_info;
DR_GROUP_SIZE (stmt_info) = groupsize;