[Mesa-dev] [PATCH] radeonsi: add a debug flag for unsafe math LLVM optimizations

[Marek Olšák]

From: Marek Olšák <marek.olsak at amd.com>

---
 src/gallium/drivers/radeon/r600_pipe_common.c |  1 +
 src/gallium/drivers/radeon/r600_pipe_common.h |  1 +
 src/gallium/drivers/radeonsi/si_shader.c      | 16 ++++++++++++++++
 3 files changed, 18 insertions(+)

diff --git a/src/gallium/drivers/radeon/r600_pipe_common.c b/src/gallium/drivers/radeon/r600_pipe_common.c
index fa9f70d..5d4a679 100644
--- a/src/gallium/drivers/radeon/r600_pipe_common.c
+++ b/src/gallium/drivers/radeon/r600_pipe_common.c
@@ -482,6 +482,7 @@ static const struct debug_named_value common_debug_options[] = {
 	{ "sisched", DBG_SI_SCHED, "Enable LLVM SI Machine Instruction Scheduler." },
 	{ "mono", DBG_MONOLITHIC_SHADERS, "Use old-style monolithic shaders compiled on demand" },
 	{ "noce", DBG_NO_CE, "Disable the constant engine"},
+	{ "unsafemath", DBG_UNSAFE_MATH, "Enable unsafe math shader optimizations" },
 
 	DEBUG_NAMED_VALUE_END /* must be last */
 };
diff --git a/src/gallium/drivers/radeon/r600_pipe_common.h b/src/gallium/drivers/radeon/r600_pipe_common.h
index 77dfc4f..263ef5e 100644
--- a/src/gallium/drivers/radeon/r600_pipe_common.h
+++ b/src/gallium/drivers/radeon/r600_pipe_common.h
@@ -99,6 +99,7 @@
 #define DBG_SI_SCHED		(1llu << 46)
 #define DBG_MONOLITHIC_SHADERS	(1llu << 47)
 #define DBG_NO_CE		(1llu << 48)
+#define DBG_UNSAFE_MATH		(1llu << 49)
 
 #define R600_MAP_BUFFER_ALIGNMENT 64
 #define R600_MAX_VIEWPORTS        16
diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index 6dc4985..bba6a55 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -5255,6 +5255,22 @@ static void si_create_function(struct si_shader_context *ctx,
 		else
 			LLVMAddAttribute(P, LLVMInRegAttribute);
 	}
+
+	if (ctx->screen->b.debug_flags & DBG_UNSAFE_MATH) {
+		/* These were copied from some LLVM test. */
+		LLVMAddTargetDependentFunctionAttr(ctx->radeon_bld.main_fn,
+						   "less-precise-fpmad",
+						   "true");
+		LLVMAddTargetDependentFunctionAttr(ctx->radeon_bld.main_fn,
+						   "no-infs-fp-math",
+						   "true");
+		LLVMAddTargetDependentFunctionAttr(ctx->radeon_bld.main_fn,
+						   "no-nans-fp-math",
+						   "true");
+		LLVMAddTargetDependentFunctionAttr(ctx->radeon_bld.main_fn,
+						   "unsafe-fp-math",
+						   "true");
+	}
 }
 
 static void create_meta_data(struct si_shader_context *ctx)
-- 
2.7.4