Mesa (main): radeonsi: limit loop unrolling for LLVM < 13

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Module: Mesa
Branch: main
Commit: eaa87b1a4659c1c06b0ac9e5659943c888dff6d3
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=eaa87b1a4659c1c06b0ac9e5659943c888dff6d3

Author: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer at amd.com>
Date:   Thu Feb  3 09:35:07 2022 +0100

radeonsi: limit loop unrolling for LLVM < 13

Without this change LLVM 12 hits this error:

"""
LLVM ERROR: Error while trying to spill SGPR0_SGPR1 from class SReg_64:
Cannot scavenge register without an emergency spill slot!
"""

when running glcts KHR-GL46.arrays_of_arrays_gl.AtomicUsage test.

Fixes: 9ff086052ab ("radeonsi: unroll loops of up to 128 iterations")
Reviewed-by: Marek Olšák <marek.olsak at amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14848>

---

 src/gallium/drivers/radeonsi/si_get.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/gallium/drivers/radeonsi/si_get.c b/src/gallium/drivers/radeonsi/si_get.c
index 795461a1c90..985daa1c776 100644
--- a/src/gallium/drivers/radeonsi/si_get.c
+++ b/src/gallium/drivers/radeonsi/si_get.c
@@ -1072,8 +1072,8 @@ void si_init_screen_get_functions(struct si_screen *sscreen)
       .has_udot_4x8 = sscreen->info.has_accelerated_dot_product,
       .has_dot_2x16 = sscreen->info.has_accelerated_dot_product,
       .optimize_sample_mask_in = true,
-      .max_unroll_iterations = 128,
-      .max_unroll_iterations_aggressive = 128,
+      .max_unroll_iterations = LLVM_VERSION_MAJOR >= 13 ? 128 : 32,
+      .max_unroll_iterations_aggressive = LLVM_VERSION_MAJOR >= 13 ? 128 : 32,
       .use_interpolated_input_intrinsics = true,
       .lower_uniforms_to_ubo = true,
       .support_16bit_alu = sscreen->options.fp16,