Mesa (master): freedreno/ir3: fix issue with emit_tex()

[Rob Clark]

Module: Mesa
Branch: master
Commit: 78ba262d004989c43b0a9e76c84b71bb16d4b333
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=78ba262d004989c43b0a9e76c84b71bb16d4b333

Author: Rob Clark <robdclark at gmail.com>
Date:   Thu Aug 11 13:27:37 2016 -0400

freedreno/ir3: fix issue with emit_tex()

For various tex fetch instructions, coord's get fixed up in different
ways.  But modifying the array returned from get_src() has side-effects
if the same SSA src is used again.. the later instruction will see the
previous fixups.

Fix this, and const'ify things to prevent this sort of mistake in the
future.

Noticed by Varad when adding support for txf_ms.

Signed-off-by: Rob Clark <robdclark at gmail.com>

---

 .../drivers/freedreno/ir3/ir3_compiler_nir.c       | 47 +++++++++++++---------
 1 file changed, 28 insertions(+), 19 deletions(-)

diff --git a/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c b/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
index 14d5e50..2331901 100644
--- a/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
+++ b/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
@@ -282,7 +282,7 @@ get_dst_ssa(struct ir3_compile *ctx, nir_ssa_def *dst, unsigned n)
 	return __get_dst(ctx, dst, n);
 }
 
-static struct ir3_instruction **
+static struct ir3_instruction * const *
 get_src(struct ir3_compile *ctx, nir_src *src)
 {
 	struct hash_entry *entry;
@@ -1105,7 +1105,8 @@ emit_intrinsic_store_var(struct ir3_compile *ctx, nir_intrinsic_instr *intr)
 	nir_deref_var *dvar = intr->variables[0];
 	nir_deref_array *darr = nir_deref_as_array(dvar->deref.child);
 	struct ir3_array *arr = get_var(ctx, dvar->var);
-	struct ir3_instruction *addr, **src;
+	struct ir3_instruction *addr;
+	struct ir3_instruction * const *src;
 	unsigned wrmask = nir_intrinsic_write_mask(intr);
 
 	compile_assert(ctx, dvar->deref.child &&
@@ -1157,7 +1158,8 @@ static void
 emit_intrinsic(struct ir3_compile *ctx, nir_intrinsic_instr *intr)
 {
 	const nir_intrinsic_info *info = &nir_intrinsic_infos[intr->intrinsic];
-	struct ir3_instruction **dst, **src;
+	struct ir3_instruction **dst;
+	struct ir3_instruction * const *src;
 	struct ir3_block *b = ctx->block;
 	nir_const_value *const_offset;
 	int idx;
@@ -1385,7 +1387,8 @@ emit_tex(struct ir3_compile *ctx, nir_tex_instr *tex)
 {
 	struct ir3_block *b = ctx->block;
 	struct ir3_instruction **dst, *sam, *src0[12], *src1[4];
-	struct ir3_instruction **coord, *lod, *compare, *proj, **off, **ddx, **ddy;
+	struct ir3_instruction * const *coord, * const *off, * const *ddx, * const *ddy;
+	struct ir3_instruction *lod, *compare, *proj;
 	bool has_bias = false, has_lod = false, has_proj = false, has_off = false;
 	unsigned i, coords, flags;
 	unsigned nsrc0 = 0, nsrc1 = 0;
@@ -1455,17 +1458,6 @@ emit_tex(struct ir3_compile *ctx, nir_tex_instr *tex)
 
 	tex_info(tex, &flags, &coords);
 
-	/* scale up integer coords for TXF based on the LOD */
-	if (ctx->unminify_coords && (opc == OPC_ISAML)) {
-		assert(has_lod);
-		for (i = 0; i < coords; i++)
-			coord[i] = ir3_SHL_B(b, coord[i], 0, lod, 0);
-	}
-
-	/* the array coord for cube arrays needs 0.5 added to it */
-	if (ctx->array_index_add_half && tex->is_array && (opc != OPC_ISAML))
-		coord[coords] = ir3_ADD_F(b, coord[coords], 0, create_immed(b, fui(0.5)), 0);
-
 	/*
 	 * lay out the first argument in the proper order:
 	 *  - actual coordinates first
@@ -1479,7 +1471,16 @@ emit_tex(struct ir3_compile *ctx, nir_tex_instr *tex)
 
 	/* insert tex coords: */
 	for (i = 0; i < coords; i++)
-		src0[nsrc0++] = coord[i];
+		src0[i] = coord[i];
+
+	nsrc0 = i;
+
+	/* scale up integer coords for TXF based on the LOD */
+	if (ctx->unminify_coords && (opc == OPC_ISAML)) {
+		assert(has_lod);
+		for (i = 0; i < coords; i++)
+			src0[i] = ir3_SHL_B(b, src0[i], 0, lod, 0);
+	}
 
 	if (coords == 1) {
 		/* hw doesn't do 1d, so we treat it as 2d with
@@ -1492,8 +1493,15 @@ emit_tex(struct ir3_compile *ctx, nir_tex_instr *tex)
 	if (tex->is_shadow && tex->op != nir_texop_lod)
 		src0[nsrc0++] = compare;
 
-	if (tex->is_array && tex->op != nir_texop_lod)
-		src0[nsrc0++] = coord[coords];
+	if (tex->is_array && tex->op != nir_texop_lod) {
+		struct ir3_instruction *idx = coord[coords];
+
+		/* the array coord for cube arrays needs 0.5 added to it */
+		if (ctx->array_index_add_half && (opc != OPC_ISAML))
+			idx = ir3_ADD_F(b, idx, 0, create_immed(b, fui(0.5)), 0);
+
+		src0[nsrc0++] = idx;
+	}
 
 	if (has_proj) {
 		src0[nsrc0++] = proj;
@@ -1621,7 +1629,8 @@ static void
 emit_tex_txs(struct ir3_compile *ctx, nir_tex_instr *tex)
 {
 	struct ir3_block *b = ctx->block;
-	struct ir3_instruction **dst, *sam, *lod;
+	struct ir3_instruction **dst, *sam;
+	struct ir3_instruction *lod;
 	unsigned flags, coords;
 
 	tex_info(tex, &flags, &coords);