[clang] [llvm] [WebAssembly] Enable nontrapping-fptoint and bulk-memory by default. (PR #112049)

[Dan Gohman via cfe-commits]

https://github.com/sunfishcode created https://github.com/llvm/llvm-project/pull/112049

We were prepared to enable these features [back in February], but they got pulled for what appear to be unrelated reasons. So let's have another try at enabling them!

Another motivation here is that it'd be convenient for the [Trail1 proposal] if "trail1" is a superset of "generic".

[back in February]: https://github.com/WebAssembly/tool-conventions/issues/158#issuecomment-1931119512
[Trail1 proposal]: https://github.com/llvm/llvm-project/pull/112035

>From 92eccc19f25177edf44c2c37f92381bcca7ff661 Mon Sep 17 00:00:00 2001
From: Dan Gohman <dev at sunfishcode.online>
Date: Fri, 11 Oct 2024 13:31:13 -0700
Subject: [PATCH] [WebAssembly] Enable nontrapping-fptoint and bulk-memory by
 default.

We were prepared to enable these features [back in February], but they
got pulled for what appear to be unrelated reasons. So let's have another
try at enabling them!

Another motivation here is that it'd be convenient for the
[Trail1 proposal] if "trail1" is a superset of "generic".

[back in February]: https://github.com/WebAssembly/tool-conventions/issues/158#issuecomment-1931119512
[Trail1 proposal]: https://github.com/llvm/llvm-project/pull/112035
---
 clang/docs/ReleaseNotes.rst                | 9 +++++++++
 clang/lib/Basic/Targets/WebAssembly.cpp    | 2 ++
 llvm/docs/ReleaseNotes.md                  | 9 +++++++++
 llvm/lib/Target/WebAssembly/WebAssembly.td | 3 ++-
 4 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index e74dd1a5fb32da..aec48e32dc85a8 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -627,6 +627,15 @@ NetBSD Support
 WebAssembly Support
 ^^^^^^^^^^^^^^^^^^^
 
+The default target CPU, "generic", now enables the `-mnontrapping-fptoint`
+and `-mbulk-memory` flags, which correspond to the [Bulk Memory Operations]
+and [Non-trapping float-to-int Conversions] language features, which are
+[widely implemented in engines].
+
+[Bulk Memory Operations]: https://github.com/WebAssembly/bulk-memory-operations/blob/master/proposals/bulk-memory-operations/Overview.md
+[Non-trapping float-to-int Conversions]: https://github.com/WebAssembly/spec/blob/master/proposals/nontrapping-float-to-int-conversion/Overview.md
+[widely implemented in engines]: https://webassembly.org/features/
+
 AVR Support
 ^^^^^^^^^^^
 
diff --git a/clang/lib/Basic/Targets/WebAssembly.cpp b/clang/lib/Basic/Targets/WebAssembly.cpp
index 5ac9421663adea..1ac8f14f8cb175 100644
--- a/clang/lib/Basic/Targets/WebAssembly.cpp
+++ b/clang/lib/Basic/Targets/WebAssembly.cpp
@@ -151,8 +151,10 @@ bool WebAssemblyTargetInfo::initFeatureMap(
     llvm::StringMap<bool> &Features, DiagnosticsEngine &Diags, StringRef CPU,
     const std::vector<std::string> &FeaturesVec) const {
   auto addGenericFeatures = [&]() {
+    Features["bulk-memory"] = true;
     Features["multivalue"] = true;
     Features["mutable-globals"] = true;
+    Features["nontrapping-fptoint"] = true;
     Features["reference-types"] = true;
     Features["sign-ext"] = true;
   };
diff --git a/llvm/docs/ReleaseNotes.md b/llvm/docs/ReleaseNotes.md
index dcdd7a25c7fbee..1d4197f25f4422 100644
--- a/llvm/docs/ReleaseNotes.md
+++ b/llvm/docs/ReleaseNotes.md
@@ -164,6 +164,15 @@ Changes to the RISC-V Backend
 Changes to the WebAssembly Backend
 ----------------------------------
 
+The default target CPU, "generic", now enables the `-mnontrapping-fptoint`
+and `-mbulk-memory` flags, which correspond to the [Bulk Memory Operations]
+and [Non-trapping float-to-int Conversions] language features, which are
+[widely implemented in engines].
+
+[Bulk Memory Operations]: https://github.com/WebAssembly/bulk-memory-operations/blob/master/proposals/bulk-memory-operations/Overview.md
+[Non-trapping float-to-int Conversions]: https://github.com/WebAssembly/spec/blob/master/proposals/nontrapping-float-to-int-conversion/Overview.md
+[widely implemented in engines]: https://webassembly.org/features/
+
 Changes to the Windows Target
 -----------------------------
 
diff --git a/llvm/lib/Target/WebAssembly/WebAssembly.td b/llvm/lib/Target/WebAssembly/WebAssembly.td
index c632d4a74355d8..1e22707db23e91 100644
--- a/llvm/lib/Target/WebAssembly/WebAssembly.td
+++ b/llvm/lib/Target/WebAssembly/WebAssembly.td
@@ -110,7 +110,8 @@ def : ProcessorModel<"mvp", NoSchedModel, []>;
 // consideration given to available support in relevant engines and tools, and
 // the importance of the features.
 def : ProcessorModel<"generic", NoSchedModel,
-                      [FeatureMultivalue, FeatureMutableGlobals,
+                      [FeatureBulkMemory, FeatureMultivalue,
+                       FeatureMutableGlobals, FeatureNontrappingFPToInt,
                        FeatureReferenceTypes, FeatureSignExt]>;
 
 // Latest and greatest experimental version of WebAssembly. Bugs included!