spirv-val: Add Vulkan FP Mode VUID (#4088)

source/val/validate_decorations.cpp

diff --git a/source/val/validate_decorations.cpp b/source/val/validate_decorations.cpp
index d381276..01b0eca 100644
--- a/source/val/validate_decorations.cpp
+++ b/source/val/validate_decorations.cpp
@@ -1260,7 +1260,8 @@
 // decorations.  Otherwise emits a diagnostic and returns something other than
 // SPV_SUCCESS.
 spv_result_t CheckFPRoundingModeForShaders(ValidationState_t& vstate,
-                                           const Instruction& inst) {
+                                           const Instruction& inst,
+                                           const Decoration& decoration) {
   // Validates width-only conversion instruction for floating-point object
   // i.e., OpFConvert
   if (inst.opcode() != SpvOpFConvert) {
@@ -1270,6 +1271,15 @@
               "object.";
   }
 
+  if (spvIsVulkanEnv(vstate.context()->target_env)) {
+    const auto mode = decoration.params()[0];
+    if ((mode != SpvFPRoundingModeRTE) && (mode != SpvFPRoundingModeRTZ)) {
+      return vstate.diag(SPV_ERROR_INVALID_ID, &inst)
+             << vstate.VkErrorID(4675)
+             << "In Vulkan, the FPRoundingMode mode must only by RTE or RTZ.";
+    }
+  }
+
   // Validates Object operand of an OpStore
   for (const auto& use : inst.uses()) {
     const auto store = use.first;
@@ -1588,7 +1598,8 @@
           break;
         case SpvDecorationFPRoundingMode:
           if (is_shader)
-            PASS_OR_BAIL(CheckFPRoundingModeForShaders(vstate, *inst));
+            PASS_OR_BAIL(
+                CheckFPRoundingModeForShaders(vstate, *inst, decoration));
           break;
         case SpvDecorationNonWritable:
           PASS_OR_BAIL(CheckNonWritableDecoration(vstate, *inst, decoration));

source/val/validation_state.cpp

diff --git a/source/val/validation_state.cpp b/source/val/validation_state.cpp
index ae34185..f56d10f 100644
--- a/source/val/validation_state.cpp
+++ b/source/val/validation_state.cpp
@@ -1671,6 +1671,8 @@
       return VUID_WRAP(VUID-StandaloneSpirv-OpTypeImage-04656);
     case 4658:
       return VUID_WRAP(VUID-StandaloneSpirv-OpImageTexelPointer-04658);
+    case 4675:
+      return VUID_WRAP(VUID-StandaloneSpirv-FPRoundingMode-04675);
     case 4685:
       return VUID_WRAP(VUID-StandaloneSpirv-OpGroupNonUniformBallotBitCount-04685);
     case 4711:

test/val/val_decoration_test.cpp

diff --git a/test/val/val_decoration_test.cpp b/test/val/val_decoration_test.cpp
index e646162..cacf999 100644
--- a/test/val/val_decoration_test.cpp
+++ b/test/val/val_decoration_test.cpp
@@ -4679,6 +4679,95 @@
                         "Object operand of an OpStore."));
 }
 
+TEST_F(ValidateDecorations, VulkanFPRoundingModeGood) {
+  std::string spirv = R"(
+               OpCapability Shader
+               OpCapability StorageBuffer16BitAccess
+          %1 = OpExtInstImport "GLSL.std.450"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %main "main" %_
+               OpExecutionMode %main LocalSize 1 1 1
+               OpMemberDecorate %ssbo 0 Offset 0
+               OpDecorate %ssbo Block
+               OpDecorate %_ DescriptorSet 0
+               OpDecorate %_ Binding 0
+               OpDecorate %17 FPRoundingMode RTE
+       %void = OpTypeVoid
+          %3 = OpTypeFunction %void
+      %float = OpTypeFloat 32
+%_ptr_Function_float = OpTypePointer Function %float
+    %float_1 = OpConstant %float 1
+       %half = OpTypeFloat 16
+       %ssbo = OpTypeStruct %half
+%_ptr_StorageBuffer_ssbo = OpTypePointer StorageBuffer %ssbo
+          %_ = OpVariable %_ptr_StorageBuffer_ssbo StorageBuffer
+        %int = OpTypeInt 32 1
+      %int_0 = OpConstant %int 0
+%_ptr_StorageBuffer_half = OpTypePointer StorageBuffer %half
+       %main = OpFunction %void None %3
+          %5 = OpLabel
+          %b = OpVariable %_ptr_Function_float Function
+               OpStore %b %float_1
+         %16 = OpLoad %float %b
+         %17 = OpFConvert %half %16
+         %19 = OpAccessChain %_ptr_StorageBuffer_half %_ %int_0
+               OpStore %19 %17
+               OpReturn
+               OpFunctionEnd
+  )";
+
+  CompileSuccessfully(spirv, SPV_ENV_VULKAN_1_2);
+  EXPECT_EQ(SPV_SUCCESS,
+            ValidateAndRetrieveValidationState(SPV_ENV_VULKAN_1_2));
+}
+
+TEST_F(ValidateDecorations, VulkanFPRoundingModeBadMode) {
+  std::string spirv = R"(
+               OpCapability Shader
+               OpCapability StorageBuffer16BitAccess
+          %1 = OpExtInstImport "GLSL.std.450"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %main "main" %_
+               OpExecutionMode %main LocalSize 1 1 1
+               OpMemberDecorate %ssbo 0 Offset 0
+               OpDecorate %ssbo Block
+               OpDecorate %_ DescriptorSet 0
+               OpDecorate %_ Binding 0
+               OpDecorate %17 FPRoundingMode RTP
+       %void = OpTypeVoid
+          %3 = OpTypeFunction %void
+      %float = OpTypeFloat 32
+%_ptr_Function_float = OpTypePointer Function %float
+    %float_1 = OpConstant %float 1
+       %half = OpTypeFloat 16
+       %ssbo = OpTypeStruct %half
+%_ptr_StorageBuffer_ssbo = OpTypePointer StorageBuffer %ssbo
+          %_ = OpVariable %_ptr_StorageBuffer_ssbo StorageBuffer
+        %int = OpTypeInt 32 1
+      %int_0 = OpConstant %int 0
+%_ptr_StorageBuffer_half = OpTypePointer StorageBuffer %half
+       %main = OpFunction %void None %3
+          %5 = OpLabel
+          %b = OpVariable %_ptr_Function_float Function
+               OpStore %b %float_1
+         %16 = OpLoad %float %b
+         %17 = OpFConvert %half %16
+         %19 = OpAccessChain %_ptr_StorageBuffer_half %_ %int_0
+               OpStore %19 %17
+               OpReturn
+               OpFunctionEnd
+  )";
+
+  CompileSuccessfully(spirv, SPV_ENV_VULKAN_1_2);
+  EXPECT_EQ(SPV_ERROR_INVALID_ID,
+            ValidateAndRetrieveValidationState(SPV_ENV_VULKAN_1_2));
+  EXPECT_THAT(getDiagnosticString(),
+              AnyVUID("VUID-StandaloneSpirv-FPRoundingMode-04675"));
+  EXPECT_THAT(
+      getDiagnosticString(),
+      HasSubstr("In Vulkan, the FPRoundingMode mode must only by RTE or RTZ."));
+}
+
 TEST_F(ValidateDecorations, GroupDecorateTargetsDecorationGroup) {
   std::string spirv = R"(
 OpCapability Shader