From c9091989f285b5c862d0c25330c83b641cfdd9a4 Mon Sep 17 00:00:00 2001
From: Igor Wodiany <igor.wodiany@imgtec.com>
Date: Thu, 1 May 2025 11:44:18 +0100
Subject: [PATCH 1/2] [mlir][spirv] Add support for RelaxedPrecision in
 function arguments

---
 .../lib/Target/SPIRV/Deserialization/Deserializer.cpp | 11 +++++++++++
 mlir/test/Target/SPIRV/decorations.mlir               |  8 ++++++++
 2 files changed, 19 insertions(+)

diff --git a/mlir/lib/Target/SPIRV/Deserialization/Deserializer.cpp b/mlir/lib/Target/SPIRV/Deserialization/Deserializer.cpp
index 1e867dde51001..9b015448a6ac2 100644
--- a/mlir/lib/Target/SPIRV/Deserialization/Deserializer.cpp
+++ b/mlir/lib/Target/SPIRV/Deserialization/Deserializer.cpp
@@ -448,6 +448,17 @@ LogicalResult spirv::Deserializer::setFunctionArgAttrs(
       foundDecorationAttr = spirv::DecorationAttr::get(context, decoration);
       break;
     }
+
+    if (decAttr.getName() == getSymbolDecoration(stringifyDecoration(
+                                 spirv::Decoration::RelaxedPrecision))) {
+      if (foundDecorationAttr)
+        return emitError(unknownLoc, "already found a decoration for function "
+                                     "argument with result <id> ")
+               << argID;
+
+      foundDecorationAttr = spirv::DecorationAttr::get(
+          context, spirv::Decoration::RelaxedPrecision);
+    }
   }
 
   if (!foundDecorationAttr)
diff --git a/mlir/test/Target/SPIRV/decorations.mlir b/mlir/test/Target/SPIRV/decorations.mlir
index d66ac74dc4ef9..fac47f7bd1086 100644
--- a/mlir/test/Target/SPIRV/decorations.mlir
+++ b/mlir/test/Target/SPIRV/decorations.mlir
@@ -151,3 +151,11 @@ spirv.module Logical GLSL450 requires #spirv.vce<v1.0, [CacheControlsINTEL], [SP
     spirv.Return
   }
 }
+
+// -----
+
+spirv.module Logical GLSL450 requires #spirv.vce<v1.0, [Shader], []> {
+  spirv.func @relaxed_precision_arg(%arg0: !spirv.ptr<f32, Function> {spirv.decoration = #spirv.decoration<RelaxedPrecision>}) -> () "None" attributes {relaxed_precision} {
+    spirv.Return
+  }
+}

From eaa3926ca41e82835c8c5d09d849ed88474abd27 Mon Sep 17 00:00:00 2001
From: Igor Wodiany <igor.wodiany@imgtec.com>
Date: Wed, 7 May 2025 11:37:14 +0100
Subject: [PATCH 2/2] Address feedback

---
 mlir/lib/Target/SPIRV/Deserialization/Deserializer.cpp | 4 ++++
 mlir/test/Target/SPIRV/decorations.mlir                | 1 +
 2 files changed, 5 insertions(+)

diff --git a/mlir/lib/Target/SPIRV/Deserialization/Deserializer.cpp b/mlir/lib/Target/SPIRV/Deserialization/Deserializer.cpp
index 9b015448a6ac2..7afd6e9b25b77 100644
--- a/mlir/lib/Target/SPIRV/Deserialization/Deserializer.cpp
+++ b/mlir/lib/Target/SPIRV/Deserialization/Deserializer.cpp
@@ -451,6 +451,10 @@ LogicalResult spirv::Deserializer::setFunctionArgAttrs(
 
     if (decAttr.getName() == getSymbolDecoration(stringifyDecoration(
                                  spirv::Decoration::RelaxedPrecision))) {
+      // TODO: Current implementation supports only one decoration per function
+      // parameter so RelaxedPrecision cannot be applied at the same time as,
+      // for example, Aliased/Restrict/etc. This should be relaxed to allow any
+      // combination of decoration allowed by the spec to be supported.
       if (foundDecorationAttr)
         return emitError(unknownLoc, "already found a decoration for function "
                                      "argument with result <id> ")
diff --git a/mlir/test/Target/SPIRV/decorations.mlir b/mlir/test/Target/SPIRV/decorations.mlir
index fac47f7bd1086..ee7ad814ea0cb 100644
--- a/mlir/test/Target/SPIRV/decorations.mlir
+++ b/mlir/test/Target/SPIRV/decorations.mlir
@@ -155,6 +155,7 @@ spirv.module Logical GLSL450 requires #spirv.vce<v1.0, [CacheControlsINTEL], [SP
 // -----
 
 spirv.module Logical GLSL450 requires #spirv.vce<v1.0, [Shader], []> {
+  // CHECK: spirv.func @relaxed_precision_arg({{%.*}}: !spirv.ptr<f32, Function> {spirv.decoration = #spirv.decoration<RelaxedPrecision>}) "None" attributes {relaxed_precision} {
   spirv.func @relaxed_precision_arg(%arg0: !spirv.ptr<f32, Function> {spirv.decoration = #spirv.decoration<RelaxedPrecision>}) -> () "None" attributes {relaxed_precision} {
     spirv.Return
   }