Mesa (master): nir: Add a load_global_constant intrinsic

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Module: Mesa
Branch: master
Commit: ff124e3fe3e89c594b91e62d3e233cfc2af3ef34
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=ff124e3fe3e89c594b91e62d3e233cfc2af3ef34

Author: Jason Ekstrand <jason at jlekstrand.net>
Date:   Sat Aug 29 00:59:22 2020 -0500

nir: Add a load_global_constant intrinsic

This has the same semantics as load_global except the memory it reads is
known to be constant so load_global_constant intrinsics can be CSEd
rather than relying on more complex copy-propagation.

Reviewed-by: Karol Herbst <kherbst at redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6379>

---

 src/compiler/nir/nir_divergence_analysis.c  | 1 +
 src/compiler/nir/nir_intrinsics.py          | 3 +++
 src/compiler/nir/nir_lower_io.c             | 1 +
 src/compiler/nir/nir_lower_phis_to_scalar.c | 1 +
 src/compiler/nir/nir_opt_gcm.c              | 1 +
 src/compiler/nir/nir_opt_shrink_vectors.c   | 1 +
 src/compiler/nir/nir_validate.c             | 1 +
 7 files changed, 9 insertions(+)

diff --git a/src/compiler/nir/nir_divergence_analysis.c b/src/compiler/nir/nir_divergence_analysis.c
index 05892b440bf..85663c83615 100644
--- a/src/compiler/nir/nir_divergence_analysis.c
+++ b/src/compiler/nir/nir_divergence_analysis.c
@@ -255,6 +255,7 @@ visit_intrinsic(nir_intrinsic_instr *instr, struct divergence_state *state)
    case nir_intrinsic_load_ssbo:
    case nir_intrinsic_load_shared:
    case nir_intrinsic_load_global:
+   case nir_intrinsic_load_global_constant:
    case nir_intrinsic_load_uniform:
    case nir_intrinsic_load_push_constant:
    case nir_intrinsic_load_constant:
diff --git a/src/compiler/nir/nir_intrinsics.py b/src/compiler/nir/nir_intrinsics.py
index 73a5bce6a27..2ef14a56984 100644
--- a/src/compiler/nir/nir_intrinsics.py
+++ b/src/compiler/nir/nir_intrinsics.py
@@ -768,6 +768,9 @@ load("constant", [1], [BASE, RANGE, ALIGN_MUL, ALIGN_OFFSET],
 # src[] = { address }.
 load("global", [1], [ACCESS, ALIGN_MUL, ALIGN_OFFSET], [CAN_ELIMINATE])
 # src[] = { address }.
+load("global_constant", [1], [ACCESS, ALIGN_MUL, ALIGN_OFFSET],
+     [CAN_ELIMINATE, CAN_REORDER])
+# src[] = { address }.
 load("kernel_input", [1], [BASE, RANGE, ALIGN_MUL, ALIGN_OFFSET], [CAN_ELIMINATE, CAN_REORDER])
 # src[] = { offset }.
 load("scratch", [1], [ALIGN_MUL, ALIGN_OFFSET], [CAN_ELIMINATE])
diff --git a/src/compiler/nir/nir_lower_io.c b/src/compiler/nir/nir_lower_io.c
index 9250a7ec1bb..1dc2a2d1bfd 100644
--- a/src/compiler/nir/nir_lower_io.c
+++ b/src/compiler/nir/nir_lower_io.c
@@ -1632,6 +1632,7 @@ nir_get_io_offset_src(nir_intrinsic_instr *instr)
    case nir_intrinsic_load_shared:
    case nir_intrinsic_load_uniform:
    case nir_intrinsic_load_global:
+   case nir_intrinsic_load_global_constant:
    case nir_intrinsic_load_scratch:
    case nir_intrinsic_load_fs_input_interp_deltas:
    case nir_intrinsic_shared_atomic_add:
diff --git a/src/compiler/nir/nir_lower_phis_to_scalar.c b/src/compiler/nir/nir_lower_phis_to_scalar.c
index 9389c8f787b..2e3cdfffc37 100644
--- a/src/compiler/nir/nir_lower_phis_to_scalar.c
+++ b/src/compiler/nir/nir_lower_phis_to_scalar.c
@@ -103,6 +103,7 @@ is_phi_src_scalarizable(nir_phi_src *src,
       case nir_intrinsic_load_ubo:
       case nir_intrinsic_load_ssbo:
       case nir_intrinsic_load_global:
+      case nir_intrinsic_load_global_constant:
       case nir_intrinsic_load_input:
          return true;
       default:
diff --git a/src/compiler/nir/nir_opt_gcm.c b/src/compiler/nir/nir_opt_gcm.c
index 02aced6b45c..6129eacd079 100644
--- a/src/compiler/nir/nir_opt_gcm.c
+++ b/src/compiler/nir/nir_opt_gcm.c
@@ -157,6 +157,7 @@ is_src_scalarizable(nir_src *src)
       case nir_intrinsic_load_ubo:
       case nir_intrinsic_load_ssbo:
       case nir_intrinsic_load_global:
+      case nir_intrinsic_load_global_constant:
       case nir_intrinsic_load_input:
          return true;
       default:
diff --git a/src/compiler/nir/nir_opt_shrink_vectors.c b/src/compiler/nir/nir_opt_shrink_vectors.c
index 0790138a749..d46b377f0ac 100644
--- a/src/compiler/nir/nir_opt_shrink_vectors.c
+++ b/src/compiler/nir/nir_opt_shrink_vectors.c
@@ -123,6 +123,7 @@ opt_shrink_vectors_intrinsic(nir_builder *b, nir_intrinsic_instr *instr)
    case nir_intrinsic_load_push_constant:
    case nir_intrinsic_load_constant:
    case nir_intrinsic_load_global:
+   case nir_intrinsic_load_global_constant:
    case nir_intrinsic_load_kernel_input:
    case nir_intrinsic_load_scratch:
    case nir_intrinsic_store_output:
diff --git a/src/compiler/nir/nir_validate.c b/src/compiler/nir/nir_validate.c
index 9d2dfbc8206..11e9841e178 100644
--- a/src/compiler/nir/nir_validate.c
+++ b/src/compiler/nir/nir_validate.c
@@ -598,6 +598,7 @@ validate_intrinsic_instr(nir_intrinsic_instr *instr, validate_state *state)
    case nir_intrinsic_load_ssbo:
    case nir_intrinsic_load_shared:
    case nir_intrinsic_load_global:
+   case nir_intrinsic_load_global_constant:
    case nir_intrinsic_load_scratch:
    case nir_intrinsic_load_constant:
       /* These memory load operations must have alignments */