disable precise i32 multiplication even in -O0: too slow

3 files changed, 3 insertions, 6 deletions

diff --git a/emcc b/emcc
index bb1a2496..ace14ece 100755
--- a/emcc
+++ b/emcc
@@ -140,12 +140,10 @@ Options that are modified or new in %s include:
                            optimizations, and no runtime assertions
                            or C++ exception catching (to re-enable
                            C++ exception catching, use
-                           -s DISABLE_EXCEPTION_CATCHING=0 ). 32-bit
-                           multiplication is done in JS doubles which
-                           is fast but imprecise for high values.
+                           -s DISABLE_EXCEPTION_CATCHING=0 ).
                            (For details on the affects of different
                            opt levels, see apply_opt_level() in
-                           tools/shared.py)
+                           tools/shared.py and also src/settings.js.)
                            Note: Optimizations are only done when
                            compiling to JavaScript, not to intermediate
                            bitcode.
diff --git a/src/settings.js b/src/settings.js
index 110cc246..cf329568 100644
--- a/src/settings.js
+++ b/src/settings.js
@@ -79,7 +79,7 @@ var PRECISE_I64_MATH = 1; // If enabled, i64 addition etc. is emulated - which i
                           // Note that we do not catch 32-bit multiplication by default (which must be done in
                           // 64 bits for high values for full precision) - you must manually set PRECISE_I32_MUL
                           // for that.
-var PRECISE_I32_MUL = 1; // If enabled, i64 math is done in i32 multiplication. This is necessary if the values
+var PRECISE_I32_MUL = 0; // If enabled, i64 math is done in i32 multiplication. This is necessary if the values
                          // exceed the JS double-integer limit of ~52 bits. This option can normally be disabled
                          // because generally i32 multiplication works ok without it, and enabling it has a big
                          // impact on performance.
diff --git a/tools/shared.py b/tools/shared.py
index 57541077..672a1a18 100644
--- a/tools/shared.py
+++ b/tools/shared.py
@@ -413,7 +413,6 @@ class Settings:
         if opt_level >= 1:
           Settings.ASSERTIONS = 0
           Settings.DISABLE_EXCEPTION_CATCHING = 1
-          Settings.PRECISE_I32_MUL = 0
         if opt_level >= 2:
           Settings.RELOOP = 1
         if opt_level >= 3: