Mesa (master): pan/midgard: Use shader stage in mir_op_computes_derivative

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Module: Mesa
Branch: master
Commit: 36633400499d109865eefd0e226fcd78cf33e02f
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=36633400499d109865eefd0e226fcd78cf33e02f

Author: Alyssa Rosenzweig <alyssa.rosenzweig at collabora.com>
Date:   Mon Nov 18 08:02:58 2019 -0500

pan/midgard: Use shader stage in mir_op_computes_derivative

A 'normal' texture op may be emitted in a vertex shader on T720 but it
still doesn't take any derivatives.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig at collabora.com>

---

 src/panfrost/midgard/compiler.h            | 2 +-
 src/panfrost/midgard/midgard_derivatives.c | 9 ++++++++-
 src/panfrost/midgard/midgard_emit.c        | 2 +-
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/panfrost/midgard/compiler.h b/src/panfrost/midgard/compiler.h
index 7e3f998ab4f..b308552e7c9 100644
--- a/src/panfrost/midgard/compiler.h
+++ b/src/panfrost/midgard/compiler.h
@@ -621,7 +621,7 @@ midgard_emit_derivatives(compiler_context *ctx, nir_alu_instr *instr);
 void
 midgard_lower_derivatives(compiler_context *ctx, midgard_block *block);
 
-bool mir_op_computes_derivatives(unsigned op);
+bool mir_op_computes_derivatives(gl_shader_stage stage, unsigned op);
 
 /* Final emission */
 
diff --git a/src/panfrost/midgard/midgard_derivatives.c b/src/panfrost/midgard/midgard_derivatives.c
index ad12293dd33..ceb3bb96166 100644
--- a/src/panfrost/midgard/midgard_derivatives.c
+++ b/src/panfrost/midgard/midgard_derivatives.c
@@ -72,12 +72,19 @@ mir_derivative_op(nir_op op)
  * implicitly */
 
 bool
-mir_op_computes_derivatives(unsigned op)
+mir_op_computes_derivatives(gl_shader_stage stage, unsigned op)
 {
+        /* Only fragment shaders may compute derivatives, but the sense of
+         * "normal" changes in vertex shaders on certain GPUs */
+
+        if (op == TEXTURE_OP_NORMAL && stage != MESA_SHADER_FRAGMENT)
+                return false;
+
         switch (op) {
         case TEXTURE_OP_NORMAL:
         case TEXTURE_OP_DFDX:
         case TEXTURE_OP_DFDY:
+                assert(stage == MESA_SHADER_FRAGMENT);
                 return true;
         default:
                 return false;
diff --git a/src/panfrost/midgard/midgard_emit.c b/src/panfrost/midgard/midgard_emit.c
index 7559a34dcfb..63dcb41ad41 100644
--- a/src/panfrost/midgard/midgard_emit.c
+++ b/src/panfrost/midgard/midgard_emit.c
@@ -430,7 +430,7 @@ emit_binary_bundle(compiler_context *ctx,
 
                 ctx->texture_op_count--;
 
-                if (mir_op_computes_derivatives(ins->texture.op)) {
+                if (mir_op_computes_derivatives(ctx->stage, ins->texture.op)) {
                         bool continues = ctx->texture_op_count > 0;
 
                         /* Control flow complicates helper invocation