From b570f48c3dfb9ca3d640467cff67e569904009d4 Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@redhat.com>
Date: Thu, 27 Feb 2025 08:48:18 +0100
Subject: [PATCH] alias: Perform offset arithmetics in poly_offset_int rather
than poly_int64 [PR118819]
This PR is about ubsan error on the c - cx1 + cy1 evaluation in the first
hunk.
The following patch hopefully fixes that by doing the additions/subtractions
in poly_offset_int rather than poly_int64 and then converting back to poly_int64.
If it doesn't fit, -1 is returned (which means it is unknown if there is a conflict
or not).
2025-02-27 Jakub Jelinek <jakub@redhat.com>
PR middle-end/118819
* alias.cc (memrefs_conflict_p): Perform arithmetics on c, xsize and
ysize in poly_offset_int and return -1 if it is not representable in
poly_int64.
---
gcc/alias.cc | 68 +++++++++++++++++++++++++++++++++++++++++++---------
1 file changed, 57 insertions(+), 11 deletions(-)
diff --git a/gcc/alias.cc b/gcc/alias.cc
index 497c2ac0e33a..4f17664c15b3 100644
--- a/gcc/alias.cc
+++ b/gcc/alias.cc
@@ -2535,19 +2535,39 @@ memrefs_conflict_p (poly_int64 xsize, rtx x, poly_int64 ysize, rtx y,
return memrefs_conflict_p (xsize, x1, ysize, y1, c);
if (poly_int_rtx_p (x1, &cx1))
{
+ poly_offset_int co = c;
+ co -= cx1;
if (poly_int_rtx_p (y1, &cy1))
- return memrefs_conflict_p (xsize, x0, ysize, y0,
- c - cx1 + cy1);
+ {
+ co += cy1;
+ if (!co.to_shwi (&c))
+ return -1;
+ return memrefs_conflict_p (xsize, x0, ysize, y0, c);
+ }
+ else if (!co.to_shwi (&c))
+ return -1;
else
- return memrefs_conflict_p (xsize, x0, ysize, y, c - cx1);
+ return memrefs_conflict_p (xsize, x0, ysize, y, c);
}
else if (poly_int_rtx_p (y1, &cy1))
- return memrefs_conflict_p (xsize, x, ysize, y0, c + cy1);
+ {
+ poly_offset_int co = c;
+ co += cy1;
+ if (!co.to_shwi (&c))
+ return -1;
+ return memrefs_conflict_p (xsize, x, ysize, y0, c);
+ }
return -1;
}
else if (poly_int_rtx_p (x1, &cx1))
- return memrefs_conflict_p (xsize, x0, ysize, y, c - cx1);
+ {
+ poly_offset_int co = c;
+ co -= cx1;
+ if (!co.to_shwi (&c))
+ return -1;
+ return memrefs_conflict_p (xsize, x0, ysize, y, c);
+ }
}
else if (GET_CODE (y) == PLUS)
{
@@ -2563,7 +2583,13 @@ memrefs_conflict_p (poly_int64 xsize, rtx x, poly_int64 ysize, rtx y,
poly_int64 cy1;
if (poly_int_rtx_p (y1, &cy1))
- return memrefs_conflict_p (xsize, x, ysize, y0, c + cy1);
+ {
+ poly_offset_int co = c;
+ co += cy1;
+ if (!co.to_shwi (&c))
+ return -1;
+ return memrefs_conflict_p (xsize, x, ysize, y0, c);
+ }
else
return -1;
}
@@ -2616,8 +2642,16 @@ memrefs_conflict_p (poly_int64 xsize, rtx x, poly_int64 ysize, rtx y,
if (maybe_gt (xsize, 0))
xsize = -xsize;
if (maybe_ne (xsize, 0))
- xsize += sc + 1;
- c -= sc + 1;
+ {
+ poly_offset_int xsizeo = xsize;
+ xsizeo += sc + 1;
+ if (!xsizeo.to_shwi (&xsize))
+ return -1;
+ }
+ poly_offset_int co = c;
+ co -= sc + 1;
+ if (!co.to_shwi (&c))
+ return -1;
return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)),
ysize, y, c);
}
@@ -2631,8 +2665,16 @@ memrefs_conflict_p (poly_int64 xsize, rtx x, poly_int64 ysize, rtx y,
if (maybe_gt (ysize, 0))
ysize = -ysize;
if (maybe_ne (ysize, 0))
- ysize += sc + 1;
- c += sc + 1;
+ {
+ poly_offset_int ysizeo = ysize;
+ ysizeo += sc + 1;
+ if (!ysizeo.to_shwi (&ysize))
+ return -1;
+ }
+ poly_offset_int co = c;
+ co += sc + 1;
+ if (!co.to_shwi (&c))
+ return -1;
return memrefs_conflict_p (xsize, x,
ysize, canon_rtx (XEXP (y, 0)), c);
}
@@ -2643,7 +2685,11 @@ memrefs_conflict_p (poly_int64 xsize, rtx x, poly_int64 ysize, rtx y,
poly_int64 cx, cy;
if (poly_int_rtx_p (x, &cx) && poly_int_rtx_p (y, &cy))
{
- c += cy - cx;
+ poly_offset_int co = c;
+ co += cy;
+ co -= cx;
+ if (!co.to_shwi (&c))
+ return -1;
return offset_overlap_p (c, xsize, ysize);
}
--
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