pan/bi: Track whether the malloc IDVS flow is used

This affects what instructions the fragment shader uses. Will be used for the
legacy geometry flow in blit shaders. Whether that is a good idea remains to be
seen, admittedly.

Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15793>

src/panfrost/bifrost/bifrost_compile.c

@@ -4336,6 +4336,7 @@ bi_compile_variant_nir(nir_shader *nir,
         ctx->arch = inputs->gpu_id >> 12;
         ctx->info = info;
         ctx->idvs = idvs;
+        ctx->malloc_idvs = (ctx->arch >= 9) && !inputs->no_idvs;
 
         if (idvs != BI_IDVS_NONE) {
                 /* Specializing shaders for IDVS is destructive, so we need to

src/panfrost/bifrost/compiler.h

@@ -728,6 +728,12 @@ typedef struct {
        unsigned arch;
        enum bi_idvs_mode idvs;
 
+       /* In any graphics shader, whether the "IDVS with memory
+        * allocation" flow is used. This affects how varyings are loaded and
+        * stored. Ignore for compute.
+        */
+       bool malloc_idvs;
+
        /* During NIR->BIR */
        bi_block *current_block;
        bi_block *after_block;