[gcc r8-10459] ldist: Further fixes for -ftrapv [PR94114]

[gcc r8-10459] ldist: Further fixes for -ftrapv [PR94114]

[Jakub Jelinek]

https://gcc.gnu.org/g:8d5332862e86edb92f27bd136ccd9fdba3524039

commit r8-10459-g8d5332862e86edb92f27bd136ccd9fdba3524039
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Mar 11 09:32:22 2020 +0100

    ldist: Further fixes for -ftrapv [PR94114]
    
    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.
    
    2020-03-11  Jakub Jelinek  <jakub@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.
    
    (cherry picked from commit 2fd27691f213f2e808626c4cd492b00c801a00fa)

Diff:
---
 gcc/testsuite/gcc.dg/pr94114.c | 13 +++++++++++++
 gcc/tree-loop-distribution.c   |  6 +++---
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/gcc/testsuite/gcc.dg/pr94114.c b/gcc/testsuite/gcc.dg/pr94114.c
new file mode 100644
index 00000000000..8d6d0eb5c2a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr94114.c
@@ -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;
+    }
+}
diff --git a/gcc/tree-loop-distribution.c b/gcc/tree-loop-distribution.c
index 05766c7300d..e257c9bc433 100644
--- a/gcc/tree-loop-distribution.c
+++ b/gcc/tree-loop-distribution.c
@@ -1001,7 +1001,7 @@ generate_memset_builtin (struct loop *loop, partition *partition)
   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);
 
@@ -1053,8 +1053,8 @@ generate_memcpy_builtin (struct loop *loop, partition *partition)
   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;