Mesa (main): nir: Fix cast

[GitLab Mirror]

Module: Mesa
Branch: main
Commit: 5997cf7587ce56aedac9114c0db9b250f1b54461
URL:    
http://cgit.freedesktop.org/mesa/mesa/commit/?id=5997cf7587ce56aedac9114c0db9b250f1b54461

Author: Matt Turner <matts...@gmail.com>
Date:   Tue Jan  9 23:45:27 2024 -0500

nir: Fix cast

We were wrongly telling `nir_const_value_as_uint()` that `iter` had
`bit_size` bits, but in one case it is explicitly i64. This works on
little endian platforms, but caused the nir_loop_unroll_test.fadd{,_rev}
tests to fail on big endian platforms.

Bug: https://bugs.gentoo.org/921297
Fixes: 268ad47c111 ("nir/loop_analyze: Handle bit sizes correctly in 
calculate_iterations")
Reviewed-by: Rhys Perry <pendingchao...@gmail.com>
Reviewed-by: Ian Romanick <ian.d.roman...@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26964>

---

 src/compiler/nir/nir_loop_analyze.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/compiler/nir/nir_loop_analyze.c 
b/src/compiler/nir/nir_loop_analyze.c
index b55da00b962..2b2ebfdd60f 100644
--- a/src/compiler/nir/nir_loop_analyze.c
+++ b/src/compiler/nir/nir_loop_analyze.c
@@ -827,6 +827,7 @@ get_iteration(nir_op cond_op, nir_const_value initial, 
nir_const_value step,
               unsigned execution_mode)
 {
    nir_const_value span, iter;
+   unsigned iter_bit_size = bit_size;
 
    switch (invert_comparison_if_needed(cond_op, invert_cond)) {
    case nir_op_ine:
@@ -880,13 +881,14 @@ get_iteration(nir_op cond_op, nir_const_value initial, 
nir_const_value step,
       iter = eval_const_binop(nir_op_fdiv, bit_size, span,
                               step, execution_mode);
       iter = eval_const_unop(nir_op_f2i64, bit_size, iter, execution_mode);
+      iter_bit_size = 64;
       break;
 
    default:
       return -1;
    }
 
-   uint64_t iter_u64 = nir_const_value_as_uint(iter, bit_size);
+   uint64_t iter_u64 = nir_const_value_as_uint(iter, iter_bit_size);
    return iter_u64 > INT_MAX ? -1 : (int)iter_u64;
 }