Attempt to turn on workflows testing for wasm.

Author: stephentyrone

.github/workflows/pull_request.yml

@@ -10,6 +10,8 @@ jobs:
     uses: swiftlang/github-workflows/.github/workflows/swift_package_test.yml@main
     with:
       windows_exclude_swift_versions: '[{"swift_version": "5.9"}]'
+      enable_wasm_sdk_build: true
+      wasm_sdk_build_command: swift build --target Numerics
   soundness:
     name: Soundness
     uses: swiftlang/github-workflows/.github/workflows/soundness.yml@main

Sources/_NumericsShims/include/_NumericsShims.h

@@ -389,6 +389,7 @@ HEADER_SHIM long double libm_lgammal(long double x, int *signp) {
 // MARK: - math inlines with relaxed semantics to support optimization.
 #define CLANG_RELAX_FP _Pragma("clang fp reassociate(on) contract(fast)")
 
+#if !defined __wasm__ // No _Float16 on wasm
 /// a + b with the "allow reassociation" and "allow FMA formation" flags
 /// set in the IR.
 HEADER_SHIM _Float16 _numerics_relaxed_addf16(_Float16 a, _Float16 b) {
@@ -402,6 +403,7 @@ HEADER_SHIM _Float16 _numerics_relaxed_mulf16(_Float16 a, _Float16 b) {
   CLANG_RELAX_FP
   return a * b;
 }
+#endif
 
 /// a + b with the "allow reassociation" and "allow FMA formation" flags
 /// set in the IR.