commit eb7865cd0d5bcbfc358540cfa191d53962deb0da
author David Neto <dneto@google.com> Mon Dec 07 23:45:47 2020 +0000
committer Commit Bot service account <commit-bot@chromium.org> Mon Dec 07 23:45:47 2020 +0000
tree 026a5e8a11dc8513104eee11a15438b6584b60f6
parent 8b0ffe91859882730306417e8ee7d056a9720283

spirv-reader: Support NClamp, NMin, NMax

Also map FClamp, FMin, FMax to WGSL "clamp", "min", and "max".
The behaviour of FClamp, FMin, and FMax doesn't specify
much when operands are NaN.  Map to WGSL functions
which are more prescriptive about results when operands are NaN.

Also add TODOs for the GLSL.std.450 instructions that I had
missed earlier: the interpolate-at instructions

Change-Id: I48503be68128d2a0659bef7057e890cb9c0617ad
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/35080
Reviewed-by: dan sinclair <dsinclair@chromium.org>
Commit-Queue: dan sinclair <dsinclair@chromium.org>
Auto-Submit: David Neto <dneto@google.com>

src/reader/spirv/function.cc

diff --git a/src/reader/spirv/function.cc b/src/reader/spirv/function.cc
index d6daa3d..ef5deaf 100644
--- a/src/reader/spirv/function.cc
+++ b/src/reader/spirv/function.cc
@@ -337,10 +337,18 @@
       return "normalize";
     case GLSLstd450UClamp:
     case GLSLstd450SClamp:
-    case GLSLstd450FClamp:
+    case GLSLstd450NClamp:
+    case GLSLstd450FClamp:  // FClamp is less prescriptive about NaN operands
       return "clamp";
     case GLSLstd450Length:
       return "length";
+    case GLSLstd450NMin:
+    case GLSLstd450FMin:  // FMin is less prescriptive about NaN operands
+      return "min";
+    case GLSLstd450NMax:
+    case GLSLstd450FMax:  // FMax is less prescriptive about NaN operands
+      return "max";
+
     default:
     // TODO(dneto). The following are not implemented.
     // They are grouped semantically, as in GLSL.std.450.h.
@@ -381,10 +389,8 @@
 
     case GLSLstd450Modf:
     case GLSLstd450ModfStruct:
-    case GLSLstd450FMin:
     case GLSLstd450UMin:
     case GLSLstd450SMin:
-    case GLSLstd450FMax:
     case GLSLstd450UMax:
     case GLSLstd450SMax:
     case GLSLstd450FMix:
@@ -418,6 +424,10 @@
     case GLSLstd450FindILsb:
     case GLSLstd450FindSMsb:
     case GLSLstd450FindUMsb:
+
+    case GLSLstd450InterpolateAtCentroid:
+    case GLSLstd450InterpolateAtSample:
+    case GLSLstd450InterpolateAtOffset:
       break;
   }
   return "";

src/reader/spirv/function_glsl_std_450_test.cc

diff --git a/src/reader/spirv/function_glsl_std_450_test.cc b/src/reader/spirv/function_glsl_std_450_test.cc
index 5de5f47..ffa1e54 100644
--- a/src/reader/spirv/function_glsl_std_450_test.cc
+++ b/src/reader/spirv/function_glsl_std_450_test.cc
@@ -467,12 +467,21 @@
 
 INSTANTIATE_TEST_SUITE_P(Samples,
                          SpvParserTest_GlslStd450_Floating_FloatingFloating,
-                         ::testing::Values(GlslStd450Case{"Atan2", "atan2"}));
+                         ::testing::ValuesIn(std::vector<GlslStd450Case>{
+                             {"Atan2", "atan2"},
+                             {"NMax", "max"},
+                             {"NMin", "min"},
+                             {"FMax", "max"},  // WGSL max promises more for NaN
+                             {"FMin", "min"}   // WGSL min promises more for NaN
+                         }));
 
 INSTANTIATE_TEST_SUITE_P(
     Samples,
     SpvParserTest_GlslStd450_Floating_FloatingFloatingFloating,
-    ::testing::Values(GlslStd450Case{"FClamp", "clamp"}));
+    ::testing::ValuesIn(std::vector<GlslStd450Case>{
+        {"NClamp", "clamp"},
+        {"FClamp", "clamp"}  // WGSL FClamp promises more for NaN
+    }));
 
 TEST_P(SpvParserTest_GlslStd450_Inting_IntingIntingInting, Scalar) {
   const auto assembly = Preamble() + R"(