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llvmpipe: Fix overflow issues calculating loop iterations for aniso

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iceil can return bogus (negative) values in case there's an overflow
(or a NaN). This would then take forever to run due to a couple billion
loop iterations.
Use unsigned minimum instead which will clamp iterations to max aniso
(not sure if that makes more sense than clamping negative values to 0,
probably doesn't really matter).

Fixes: 350a0fe632 ("llvmpipe: Use a simpler and faster AF implementation")

Reviewed-by: Brian Paul <brian.paul@broadcom.com>
Reviewed-by: Konstantin Seurer <konstantin.seurer@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33537>
This commit is contained in:
Roland Scheidegger 2025-02-13 23:38:48 +01:00 • committed by Marge Bot
parent cc30e35306
commit 24076eb3f9
1 changed files with 7 additions and 1 deletions
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8
src/gallium/auxiliary/gallivm/lp_bld_sample_soa.c
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@ -2198,9 +2198,13 @@ lp_build_sample_aniso(struct lp_build_sample_context *bld,
LLVMBuilderRef builder = gallivm->builder;
struct lp_build_context *coord_bld = &bld->coord_bld;
struct lp_build_context *int_coord_bld = &bld->int_coord_bld;
struct lp_build_context uint_coord_bld;
LLVMValueRef size0, row_stride0_vec, img_stride0_vec;
LLVMValueRef data_ptr0, mipoff0 = NULL;
lp_build_context_init(&uint_coord_bld, gallivm, lp_uint_type(int_coord_bld->type));
lp_build_mipmap_level_sizes(bld, ilevel0,
&size0,
&row_stride0_vec, &img_stride0_vec);
@ -2243,7 +2247,9 @@ lp_build_sample_aniso(struct lp_build_sample_context *bld,
/* Number of samples used for averaging. */
LLVMValueRef N = lp_build_iceil(coord_bld, lp_build_max(coord_bld, rho_x, rho_y));
N = lp_build_min(int_coord_bld, N, lp_build_const_int_vec(gallivm, int_coord_bld->type, bld->static_sampler_state->aniso));
/* Use uint min so in case of NaNs/overflows loop iterations are clamped to max aniso */
N = lp_build_min(&uint_coord_bld, N, lp_build_const_int_vec(gallivm, int_coord_bld->type, bld->static_sampler_state->aniso));
LLVMValueRef wave_max_N = NULL;
for (uint32_t i = 0; i < coord_bld->type.length; i++) {
LLVMValueRef invocation_N = LLVMBuildExtractElement(builder, N, lp_build_const_int32(gallivm, i), "");