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Fix: Cycles: Ubsan warnings with new voronoi texture hashing

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Signed integer overflow is undefined, but works reliably enough for us
anyway, so just silence it like the Blender implementation already does.

This also caused some tests like cycles_displacement_cpu to run much slower
(3s -> 42s) due to the overhead of detecting and ignoring repeated warnings.

Pull Request: https://projects.blender.org/blender/blender/pulls/146783
This commit is contained in:
Brecht Van Lommel
2025-09-25 17:48:22 +02:00
committed by Brecht Van Lommel
parent b74e696acc
commit 57342a51f8
2 changed files with 19 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
intern/cycles/util/defines.h
View File

@@ -82,6 +82,18 @@
# endif
#endif /* __KERNEL_GPU__ */
/* Address sanitizer suppression. */
#ifdef __KERNEL_GPU__
# define ccl_ignore_integer_overflow
#else
# if defined(__SANITIZE_ADDRESS__) && (defined(__GNUC__) || defined(__clang__))
# define ccl_ignore_integer_overflow [[gnu::no_sanitize("signed-integer-overflow")]]
# else
# define ccl_ignore_integer_overflow
# endif
#endif
/* macros */
/* hints for branch prediction, only use in code that runs a _lot_ */

11
intern/cycles/util/hash.h
View File

@@ -4,6 +4,7 @@
#pragma once
#include "util/defines.h"
#include "util/math.h"
#include "util/types.h"
@@ -31,9 +32,11 @@ ccl_device_forceinline float uint_to_float_incl(const uint n)
* https://jcgt.org/published/0009/03/02/
*
* Slightly modified to only use signed integers,
* so that they can also be implemented in OSL. */
* so that they can also be implemented in OSL.
*
* Silence UBsan warnings about signed integer overflow. */
ccl_device_inline int2 hash_pcg2d_i(int2 v)
ccl_ignore_integer_overflow ccl_device_inline int2 hash_pcg2d_i(int2 v)
{
v = v * make_int2(1664525) + make_int2(1013904223);
v.x += v.y * 1664525;
@@ -44,7 +47,7 @@ ccl_device_inline int2 hash_pcg2d_i(int2 v)
return v & make_int2(0x7FFFFFFF);
}
ccl_device_inline int3 hash_pcg3d_i(int3 v)
ccl_ignore_integer_overflow ccl_device_inline int3 hash_pcg3d_i(int3 v)
{
v = v * make_int3(1664525) + make_int3(1013904223);
v.x += v.y * v.z;
@@ -57,7 +60,7 @@ ccl_device_inline int3 hash_pcg3d_i(int3 v)
return v & make_int3(0x7FFFFFFF);
}
ccl_device_inline int4 hash_pcg4d_i(int4 v)
ccl_ignore_integer_overflow ccl_device_inline int4 hash_pcg4d_i(int4 v)
{
v = v * make_int4(1664525) + make_int4(1013904223);
v.x += v.y * v.w;