[Mesa-dev] [PATCH] radv: run the EarlyCSEMemSSA LLVM pass

[Samuel Pitoiset]

It's recommended by the instruction combining pass, and
RadeonSI also runs it.

This pass used to segfault with one shader of F12017 but it
has been fixed somewhere in LLVM 7.

Polaris10:
Totals from affected shaders:
SGPRS: 441352 -> 441648 (0.07 %)
VGPRS: 310888 -> 300784 (-3.25 %)
Spilled SGPRs: 13576 -> 12983 (-4.37 %)
Code Size: 22560328 -> 22420544 (-0.62 %) bytes
Max Waves: 40755 -> 41366 (1.50 %)

Vega10:
Totals from affected shaders:
SGPRS: 442848 -> 442000 (-0.19 %)
VGPRS: 310396 -> 300460 (-3.20 %)
Spilled SGPRs: 13708 -> 12906 (-5.85 %)
Code Size: 22479428 -> 22336216 (-0.64 %) bytes
Max Waves: 45783 -> 46506 (1.58 %)

Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
---
 src/amd/vulkan/radv_nir_to_llvm.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/amd/vulkan/radv_nir_to_llvm.c b/src/amd/vulkan/radv_nir_to_llvm.c
index b174c027d9..d89c22ea06 100644
--- a/src/amd/vulkan/radv_nir_to_llvm.c
+++ b/src/amd/vulkan/radv_nir_to_llvm.c
@@ -2982,6 +2982,12 @@ static void ac_llvm_finalize_module(struct radv_shader_context *ctx)
 	LLVMAddLICMPass(passmgr);
 	LLVMAddAggressiveDCEPass(passmgr);
 	LLVMAddCFGSimplificationPass(passmgr);
+#if HAVE_LLVM >= 0x0700
+	/* XXX: This LLVM pass used to segfault with one shader of F12017. This
+	 * has been fixed somewhere in LLVM 7. */
+	/* This is recommended by the instruction combining pass. */
+	LLVMAddEarlyCSEMemSSAPass(passmgr);
+#endif
 	LLVMAddInstructionCombiningPass(passmgr);
 
 	/* Run the pass */
-- 
2.17.0