Mesa (master): spirv: Call repair SSA for OpTerminateInvocation

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Module: Mesa
Branch: master
Commit: 66685679b7c047398d3f593db86a24eba38db3b9
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=66685679b7c047398d3f593db86a24eba38db3b9

Author: Jason Ekstrand <jason.ekstrand at intel.com>
Date:   Mon Nov 23 10:07:17 2020 -0600

spirv: Call repair SSA for OpTerminateInvocation

Fixes: 886d2d1a9abcb "spirv: Handle SpvOpTerminateInvocation"

Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira at intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7734>

---

 src/compiler/spirv/vtn_cfg.c     |  6 ++++--
 src/compiler/spirv/vtn_private.h | 14 +++++++++++++-
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/src/compiler/spirv/vtn_cfg.c b/src/compiler/spirv/vtn_cfg.c
index 41622752f36..4d68f8f34da 100644
--- a/src/compiler/spirv/vtn_cfg.c
+++ b/src/compiler/spirv/vtn_cfg.c
@@ -687,11 +687,12 @@ vtn_process_block(struct vtn_builder *b,
       return NULL;
 
    case SpvOpKill:
-      b->has_kill = true;
+      b->has_early_terminate = true;
       block->branch_type = vtn_branch_type_discard;
       return NULL;
 
    case SpvOpTerminateInvocation:
+      b->has_early_terminate = true;
       block->branch_type = vtn_branch_type_terminate;
       return NULL;
 
@@ -1377,7 +1378,8 @@ vtn_function_emit(struct vtn_builder *b, struct vtn_function *func,
     * but instructions in the continue may use SSA defs in the loop body.
     * Therefore, we need to repair SSA to insert the needed phi nodes.
     */
-   if (b->func->impl->structured && (b->has_loop_continue || b->has_kill))
+   if (b->func->impl->structured &&
+       (b->has_loop_continue || b->has_early_terminate))
       nir_repair_ssa_impl(func->impl);
 
    func->emitted = true;
diff --git a/src/compiler/spirv/vtn_private.h b/src/compiler/spirv/vtn_private.h
index 97fc67f8493..3d32db83312 100644
--- a/src/compiler/spirv/vtn_private.h
+++ b/src/compiler/spirv/vtn_private.h
@@ -702,7 +702,19 @@ struct vtn_builder {
    unsigned func_param_idx;
 
    bool has_loop_continue;
-   bool has_kill;
+
+   /** True if this shader has any early termination instructions like OpKill
+    *
+    * In the SPIR-V, the following instructions are block terminators:
+    *
+    *  - OpKill
+    *  - OpTerminateInvocation
+    *
+    * However, in NIR, they're represented by regular intrinsics with no
+    * control-flow semantics.  This means that the SSA form from the SPIR-V
+    * may not 100% match NIR and we have to fix it up at the end.
+    */
+   bool has_early_terminate;
 
    /* false by default, set to true by the ContractionOff execution mode */
    bool exact;