Remove FAST_MATH internal settings (#25634)

This was just added #25513, but using a setting for this was overkill.

Author: sbc100

src/settings_internal.js

@@ -260,11 +260,6 @@ var ASYNCIFY_IMPORTS_EXCEPT_JS_LIBS = [];
 
 var WARN_DEPRECATED = true;
 
-// Enable fast math optimizations in wasm-opt when -ffast-math is passed.
-// This enables aggressive floating-point optimizations that may violate
-// IEEE 754 semantics but can improve performance.
-var FAST_MATH = 0;
-
 // WebGL 2 provides new garbage-free entry points to call to WebGL. Use
 // those always when possible.
 // We currently set this to false for certain browser when large memory sizes

tools/cmdline.py

@@ -112,6 +112,7 @@ def __init__(self):
     self.sanitize_minimal_runtime = False
     self.sanitize = set()
     self.lib_dirs = []
+    self.fast_math = False
 
 
 def is_int(s):
@@ -302,7 +303,7 @@ def consume_arg_file():
         settings.DEBUG_LEVEL = max(settings.DEBUG_LEVEL, 1)
       elif requested_level == 'fast':
         # -Ofast typically includes -ffast-math semantics
-        settings.FAST_MATH = 1
+        options.fast_math = True
         requested_level = 3
         settings.SHRINK_LEVEL = 0
       else:
@@ -552,7 +553,7 @@ def consume_arg_file():
     elif arg == '-fignore-exceptions':
       settings.DISABLE_EXCEPTION_CATCHING = 1
     elif arg == '-ffast-math':
-      settings.FAST_MATH = 1
+      options.fast_math = True
     elif check_arg('--default-obj-ext'):
       exit_with_error('--default-obj-ext is no longer supported by emcc')
     elif arg.startswith('-fsanitize=cfi'):

tools/link.py

@@ -360,7 +360,7 @@ def should_run_binaryen_optimizer():
   return settings.OPT_LEVEL >= 2
 
 
-def get_binaryen_passes():
+def get_binaryen_passes(options):
   passes = []
   optimizing = should_run_binaryen_optimizer()
   # wasm-emscripten-finalize will strip the features section for us
@@ -392,7 +392,7 @@ def get_binaryen_passes():
       passes += ['--pass-arg=post-emscripten-side-module']
   if optimizing:
     passes += [building.opt_level_to_str(settings.OPT_LEVEL, settings.SHRINK_LEVEL)]
-  if settings.FAST_MATH:
+  if options.fast_math:
     passes += ['--fast-math']
   # when optimizing, use the fact that low memory is never used (1024 is a
   # hardcoded value in the binaryen pass). we also cannot do it when the stack
@@ -2292,7 +2292,7 @@ def phase_binaryen(target, options, wasm_target):
   # run wasm-opt if we have work for it: either passes, or if we are using
   # source maps (which requires some extra processing to keep the source map
   # but remove DWARF)
-  passes = get_binaryen_passes()
+  passes = get_binaryen_passes(options)
   if passes:
     # if asyncify is used, we will use it in the next stage, and so if it is
     # the only reason we need intermediate debug info, we can stop keeping it