radeonsi: enable denorms for 64-bit and 16-bit floats

This fixes FP16 conversion instructions for VI, which has 16-bit floats,
but not SI & CI, which can't disable denorms for those instructions.

Reviewed-by: Nicolai Hähnle <[email protected]>

3 files changed, 29 insertions, 6 deletions

diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index 15a6a049050..c1d3edc7143 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -4119,6 +4119,20 @@ int si_compile_llvm(struct si_screen *sscreen,
 
 	si_shader_binary_read_config(binary, conf, 0);
 
+	/* Enable 64-bit and 16-bit denormals, because there is no performance
+	 * cost.
+	 *
+	 * If denormals are enabled, all floating-point output modifiers are
+	 * ignored.
+	 *
+	 * Don't enable denormals for 32-bit floats, because:
+	 * - Floating-point output modifiers would be ignored by the hw.
+	 * - Some opcodes don't support denormals, such as v_mad_f32. We would
+	 *   have to stop using those.
+	 * - SI & CI would be very slow.
+	 */
+	conf->float_mode |= V_00B028_FP_64_DENORMS;
+
 	FREE(binary->config);
 	FREE(binary->global_symbol_offsets);
 	binary->config = NULL;
diff --git a/src/gallium/drivers/radeonsi/si_state_shaders.c b/src/gallium/drivers/radeonsi/si_state_shaders.c
index ce795c02c32..77a4e47c809 100644
--- a/src/gallium/drivers/radeonsi/si_state_shaders.c
+++ b/src/gallium/drivers/radeonsi/si_state_shaders.c
@@ -124,7 +124,8 @@ static void si_shader_ls(struct si_shader *shader)
 	shader->config.rsrc1 = S_00B528_VGPRS((shader->config.num_vgprs - 1) / 4) |
 			   S_00B528_SGPRS((num_sgprs - 1) / 8) |
 		           S_00B528_VGPR_COMP_CNT(vgpr_comp_cnt) |
-			   S_00B528_DX10_CLAMP(1);
+			   S_00B528_DX10_CLAMP(1) |
+			   S_00B528_FLOAT_MODE(shader->config.float_mode);
 	shader->config.rsrc2 = S_00B52C_USER_SGPR(num_user_sgprs) |
 			   S_00B52C_SCRATCH_EN(shader->config.scratch_bytes_per_wave > 0);
 }
@@ -157,7 +158,8 @@ static void si_shader_hs(struct si_shader *shader)
 	si_pm4_set_reg(pm4, R_00B428_SPI_SHADER_PGM_RSRC1_HS,
 		       S_00B428_VGPRS((shader->config.num_vgprs - 1) / 4) |
 		       S_00B428_SGPRS((num_sgprs - 1) / 8) |
-		       S_00B428_DX10_CLAMP(1));
+		       S_00B428_DX10_CLAMP(1) |
+		       S_00B428_FLOAT_MODE(shader->config.float_mode));
 	si_pm4_set_reg(pm4, R_00B42C_SPI_SHADER_PGM_RSRC2_HS,
 		       S_00B42C_USER_SGPR(num_user_sgprs) |
 		       S_00B42C_SCRATCH_EN(shader->config.scratch_bytes_per_wave > 0));
@@ -203,7 +205,8 @@ static void si_shader_es(struct si_shader *shader)
 		       S_00B328_VGPRS((shader->config.num_vgprs - 1) / 4) |
 		       S_00B328_SGPRS((num_sgprs - 1) / 8) |
 		       S_00B328_VGPR_COMP_CNT(vgpr_comp_cnt) |
-		       S_00B328_DX10_CLAMP(1));
+		       S_00B328_DX10_CLAMP(1) |
+		       S_00B328_FLOAT_MODE(shader->config.float_mode));
 	si_pm4_set_reg(pm4, R_00B32C_SPI_SHADER_PGM_RSRC2_ES,
 		       S_00B32C_USER_SGPR(num_user_sgprs) |
 		       S_00B32C_SCRATCH_EN(shader->config.scratch_bytes_per_wave > 0));
@@ -292,7 +295,8 @@ static void si_shader_gs(struct si_shader *shader)
 	si_pm4_set_reg(pm4, R_00B228_SPI_SHADER_PGM_RSRC1_GS,
 		       S_00B228_VGPRS((shader->config.num_vgprs - 1) / 4) |
 		       S_00B228_SGPRS((num_sgprs - 1) / 8) |
-		       S_00B228_DX10_CLAMP(1));
+		       S_00B228_DX10_CLAMP(1) |
+		       S_00B228_FLOAT_MODE(shader->config.float_mode));
 	si_pm4_set_reg(pm4, R_00B22C_SPI_SHADER_PGM_RSRC2_GS,
 		       S_00B22C_USER_SGPR(num_user_sgprs) |
 		       S_00B22C_SCRATCH_EN(shader->config.scratch_bytes_per_wave > 0));
@@ -381,7 +385,8 @@ static void si_shader_vs(struct si_shader *shader, struct si_shader *gs)
 		       S_00B128_VGPRS((shader->config.num_vgprs - 1) / 4) |
 		       S_00B128_SGPRS((num_sgprs - 1) / 8) |
 		       S_00B128_VGPR_COMP_CNT(vgpr_comp_cnt) |
-		       S_00B128_DX10_CLAMP(1));
+		       S_00B128_DX10_CLAMP(1) |
+		       S_00B128_FLOAT_MODE(shader->config.float_mode));
 	si_pm4_set_reg(pm4, R_00B12C_SPI_SHADER_PGM_RSRC2_VS,
 		       S_00B12C_USER_SGPR(num_user_sgprs) |
 		       S_00B12C_SO_BASE0_EN(!!shader->selector->so.stride[0]) |
@@ -567,7 +572,8 @@ static void si_shader_ps(struct si_shader *shader)
 	si_pm4_set_reg(pm4, R_00B028_SPI_SHADER_PGM_RSRC1_PS,
 		       S_00B028_VGPRS((shader->config.num_vgprs - 1) / 4) |
 		       S_00B028_SGPRS((num_sgprs - 1) / 8) |
-		       S_00B028_DX10_CLAMP(1));
+		       S_00B028_DX10_CLAMP(1) |
+		       S_00B028_FLOAT_MODE(shader->config.float_mode));
 	si_pm4_set_reg(pm4, R_00B02C_SPI_SHADER_PGM_RSRC2_PS,
 		       S_00B02C_EXTRA_LDS_SIZE(shader->config.lds_size) |
 		       S_00B02C_USER_SGPR(num_user_sgprs) |
diff --git a/src/gallium/drivers/radeonsi/sid.h b/src/gallium/drivers/radeonsi/sid.h
index 9e1e158219f..892084707d2 100644
--- a/src/gallium/drivers/radeonsi/sid.h
+++ b/src/gallium/drivers/radeonsi/sid.h
@@ -2845,6 +2845,9 @@
 #define   S_00B028_FLOAT_MODE(x)                                      (((x) & 0xFF) << 12)
 #define   G_00B028_FLOAT_MODE(x)                                      (((x) >> 12) & 0xFF)
 #define   C_00B028_FLOAT_MODE                                         0xFFF00FFF
+#define     V_00B028_FP_32_DENORMS					0x30
+#define     V_00B028_FP_64_DENORMS					0xc0
+#define     V_00B028_FP_ALL_DENORMS					0xf0
 #define   S_00B028_PRIV(x)                                            (((x) & 0x1) << 20)
 #define   G_00B028_PRIV(x)                                            (((x) >> 20) & 0x1)
 #define   C_00B028_PRIV                                               0xFFEFFFFF