Hi!
As the testcase shows, arithmetics that for -ftrapv would need multiple
basic blocks can show up not just in nb_bytes expressions where we
are calling rewrite_to_non_trapping_overflow for a while already,
but also in the pointer expression to the start of the region.
While the testcase covers just the first hunk and I've failed to create
a testcase for the latter, it is at least in theory possible too, so I've
adjusted that hunk too.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2020-03-11 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/94114
* tree-loop-distribution.c (generate_memset_builtin): Call
rewrite_to_non_trapping_overflow even on mem.
(generate_memcpy_builtin): Call rewrite_to_non_trapping_overflow even
on dest and src.
* gcc.dg/pr94114.c: New test.
--- gcc/tree-loop-distribution.c.jj 2020-01-12 11:54:38.497381967 +0100
+++ gcc/tree-loop-distribution.c 2020-03-10 08:20:42.830265273 +0100
@@ -1151,7 +1151,7 @@ generate_memset_builtin (class loop *loo
nb_bytes = rewrite_to_non_trapping_overflow (builtin->size);
nb_bytes = force_gimple_operand_gsi (&gsi, nb_bytes, true, NULL_TREE,
false, GSI_CONTINUE_LINKING);
- mem = builtin->dst_base;
+ mem = rewrite_to_non_trapping_overflow (builtin->dst_base);
mem = force_gimple_operand_gsi (&gsi, mem, true, NULL_TREE,
false, GSI_CONTINUE_LINKING);
@@ -1205,8 +1205,8 @@ generate_memcpy_builtin (class loop *loo
nb_bytes = rewrite_to_non_trapping_overflow (builtin->size);
nb_bytes = force_gimple_operand_gsi (&gsi, nb_bytes, true, NULL_TREE,
false, GSI_CONTINUE_LINKING);
- dest = builtin->dst_base;
- src = builtin->src_base;
+ dest = rewrite_to_non_trapping_overflow (builtin->dst_base);
+ src = rewrite_to_non_trapping_overflow (builtin->src_base);
if (partition->kind == PKIND_MEMCPY
|| ! ptr_derefs_may_alias_p (dest, src))
kind = BUILT_IN_MEMCPY;
--- gcc/testsuite/gcc.dg/pr94114.c.jj 2020-03-10 08:21:07.369900379 +0100
+++ gcc/testsuite/gcc.dg/pr94114.c 2020-03-10 08:19:06.691694811 +0100
@@ -0,0 +1,13 @@
+/* PR tree-optimization/94114 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -ftree-loop-distribute-patterns -ftrapv" } */
+
+void
+foo (int *x, int *y, int *z, long int w)
+{
+ while (y + w > z)
+ {
+ x[w] = 0;
+ --w;
+ }
+}
Jakub
