diff --git a/src/asm2wasm.h b/src/asm2wasm.h
index e2b1802b53f..9abfe7432b3 100644
--- a/src/asm2wasm.h
+++ b/src/asm2wasm.h
@@ -675,6 +675,19 @@ class Asm2WasmBuilder {
     return ret;
   }
 
+  // converts an f32 to an f64 if necessary
+  Expression* ensureDouble(Expression* expr) {
+    if (expr->type == f32) {
+      auto conv = allocator.alloc<Unary>();
+      conv->op = PromoteFloat32;
+      conv->value = expr;
+      conv->type = WasmType::f64;
+      return conv;
+    }
+    assert(expr->type == f64);
+    return expr;
+  }
+
   // Some binary opts might trap, so emit them safely if necessary
   Expression* makeTrappingI32Binary(BinaryOp op, Expression* left, Expression* right) {
     if (trapMode == TrapMode::Allow) return builder.makeBinary(op, left, right);
@@ -803,14 +816,7 @@ class Asm2WasmBuilder {
     }
     // WebAssembly traps on float-to-int overflows, but asm.js wouldn't, so we must do something
     // First, normalize input to f64
-    auto input = value;
-    if (input->type == f32) {
-      auto conv = allocator.alloc<Unary>();
-      conv->op = PromoteFloat32;
-      conv->value = input;
-      conv->type = WasmType::f64;
-      input = conv;
-    }
+    auto input = ensureDouble(value);
     // We can handle this in one of two ways: clamping, which is fast, or JS, which
     // is precisely like JS but in order to do that we do a slow ffi
     if (trapMode == TrapMode::JS) {
@@ -894,14 +900,7 @@ class Asm2WasmBuilder {
     }
     // WebAssembly traps on float-to-int overflows, but asm.js wouldn't, so we must do something
     // First, normalize input to f64
-    auto input = value;
-    if (input->type == f32) {
-      auto conv = allocator.alloc<Unary>();
-      conv->op = PromoteFloat32;
-      conv->value = input;
-      conv->type = WasmType::f64;
-      input = conv;
-    }
+    auto input = ensureDouble(value);
     // There is no "JS" way to handle this, as no i64s in JS, so always clamp if we don't allow traps
     Call *ret = allocator.alloc<Call>();
     ret->target = F64_TO_INT64;
@@ -1795,11 +1794,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
           conv->type = WasmType::f32;
           ret->value = conv;
         } else if (ret->valueType == f64 && ret->value->type == f32) {
-          auto conv = allocator.alloc<Unary>();
-          conv->op = PromoteFloat32;
-          conv->value = ret->value;
-          conv->type = WasmType::f64;
-          ret->value = conv;
+          ret->value = ensureDouble(ret->value);
         } else {
           abort_on("bad sub[] types", ast);
         }
@@ -1822,8 +1817,8 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
         // WebAssembly does not have floating-point remainder, we have to emit a call to a special import of ours
         CallImport *call = allocator.alloc<CallImport>();
         call->target = F64_REM;
-        call->operands.push_back(ret->left);
-        call->operands.push_back(ret->right);
+        call->operands.push_back(ensureDouble(ret->left));
+        call->operands.push_back(ensureDouble(ret->right));
         call->type = f64;
         static bool addedImport = false;
         if (!addedImport) {
@@ -1873,11 +1868,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
           return conv;
         }
         if (ret->type == f32) {
-          auto conv = allocator.alloc<Unary>();
-          conv->op = PromoteFloat32;
-          conv->value = ret;
-          conv->type = WasmType::f64;
-          return conv;
+          return ensureDouble(ret);
         }
         fixCallType(ret, f64);
         return ret;
@@ -2485,11 +2476,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
                   conv->value = process(writtenValue);
                   conv->type = WasmType::f32;
                   if (readType == ASM_DOUBLE) {
-                    auto promote = allocator.alloc<Unary>();
-                    promote->op = PromoteFloat32;
-                    promote->value = conv;
-                    promote->type = WasmType::f64;
-                    return promote;
+                    return ensureDouble(conv);
                   }
                   return conv;
                 } else if (writeType == ASM_FLOAT && readType == ASM_INT) {
diff --git a/test/unit.asm.js b/test/unit.asm.js
index 22e18007848..0655120119a 100644
--- a/test/unit.asm.js
+++ b/test/unit.asm.js
@@ -137,6 +137,9 @@ function asm(global, env, buffer) {
   function frem() {
     return +(5.5 % 1.2);
   }
+  function frem_float() {
+    return Math_fround(Math_fround(5.5) % Math_fround(1.2));
+  }
   function big_uint_div_u() {
     var x = 0;
     x = (4294967295 / 2)&-1;
@@ -740,6 +743,6 @@ function asm(global, env, buffer) {
   var FUNCTION_TABLE_vi = [ vi, vi, vi, vi, vi, vi, vi, vi ];
   var FUNCTION_TABLE_ii = [ ii ];
 
-  return { big_negative: big_negative, pick: forgetMe, pick: exportMe, doubleCompares: doubleCompares, intOps: intOps, conversions: conversions, switcher: switcher, frem: frem, big_uint_div_u: big_uint_div_u, fr: fr, negZero: negZero, neg: neg, smallCompare: smallCompare, cneg_nosemicolon: cneg_nosemicolon, forLoop: forLoop, ceiling_32_64: ceiling_32_64, aborts: aborts, continues: continues, bitcasts: bitcasts, recursiveBlockMerging: recursiveBlockMerging, lb: lb, zeroInit: zeroInit, phi: phi, smallIf: smallIf, dropCall: dropCall, useSetGlobal: useSetGlobal, usesSetGlobal2: usesSetGlobal2, breakThroughMany: breakThroughMany, ifChainEmpty: ifChainEmpty, heap8NoShift: heap8NoShift, conditionalTypeFun: conditionalTypeFun, loadSigned: loadSigned, globalOpts: globalOpts, dropCallImport: dropCallImport, loophi: loophi, loophi2: loophi2, relooperJumpThreading: relooperJumpThreading, relooperJumpThreading__ZN4game14preloadweaponsEv: relooperJumpThreading__ZN4game14preloadweaponsEv, __Z12multi_varargiz: __Z12multi_varargiz, jumpThreadDrop: jumpThreadDrop, dropIgnoredImportInIf: dropIgnoredImportInIf, dropIgnoredImportsInIf: dropIgnoredImportsInIf, relooperJumpThreading_irreducible: relooperJumpThreading_irreducible, store_fround: store_fround, exportedNumber: 42, relocatableAndModules: relocatableAndModules, exported_f32_user: exported_f32_user, keepAlive: keepAlive };
+  return { big_negative: big_negative, pick: forgetMe, pick: exportMe, doubleCompares: doubleCompares, intOps: intOps, conversions: conversions, switcher: switcher, frem: frem, frem_float: frem_float, big_uint_div_u: big_uint_div_u, fr: fr, negZero: negZero, neg: neg, smallCompare: smallCompare, cneg_nosemicolon: cneg_nosemicolon, forLoop: forLoop, ceiling_32_64: ceiling_32_64, aborts: aborts, continues: continues, bitcasts: bitcasts, recursiveBlockMerging: recursiveBlockMerging, lb: lb, zeroInit: zeroInit, phi: phi, smallIf: smallIf, dropCall: dropCall, useSetGlobal: useSetGlobal, usesSetGlobal2: usesSetGlobal2, breakThroughMany: breakThroughMany, ifChainEmpty: ifChainEmpty, heap8NoShift: heap8NoShift, conditionalTypeFun: conditionalTypeFun, loadSigned: loadSigned, globalOpts: globalOpts, dropCallImport: dropCallImport, loophi: loophi, loophi2: loophi2, relooperJumpThreading: relooperJumpThreading, relooperJumpThreading__ZN4game14preloadweaponsEv: relooperJumpThreading__ZN4game14preloadweaponsEv, __Z12multi_varargiz: __Z12multi_varargiz, jumpThreadDrop: jumpThreadDrop, dropIgnoredImportInIf: dropIgnoredImportInIf, dropIgnoredImportsInIf: dropIgnoredImportsInIf, relooperJumpThreading_irreducible: relooperJumpThreading_irreducible, store_fround: store_fround, exportedNumber: 42, relocatableAndModules: relocatableAndModules, exported_f32_user: exported_f32_user, keepAlive: keepAlive };
 }
 
diff --git a/test/unit.fromasm b/test/unit.fromasm
index 68f5920ee34..020ded16322 100644
--- a/test/unit.fromasm
+++ b/test/unit.fromasm
@@ -33,6 +33,7 @@
  (export "conversions" (func $conversions))
  (export "switcher" (func $switcher))
  (export "frem" (func $frem))
+ (export "frem_float" (func $legalstub$frem_float))
  (export "big_uint_div_u" (func $big_uint_div_u))
  (export "fr" (func $legalstub$fr))
  (export "negZero" (func $negZero))
@@ -245,6 +246,14 @@
    (f64.const 1.2)
   )
  )
+ (func $frem_float (result f32)
+  (f32.demote/f64
+   (call $f64-rem
+    (f64.const 5.5)
+    (f64.const 1.2000000476837158)
+   )
+  )
+ )
  (func $i32u-div (param $0 i32) (param $1 i32) (result i32)
   (if (result i32)
    (get_local $1)
@@ -1217,6 +1226,11 @@
  (func $ii (param $0 i32) (result i32)
   (get_local $0)
  )
+ (func $legalstub$frem_float (result f64)
+  (f64.promote/f32
+   (call $frem_float)
+  )
+ )
  (func $legalstub$fr (param $0 f64)
   (call $fr
    (f32.demote/f64
diff --git a/test/unit.fromasm.clamp b/test/unit.fromasm.clamp
index 1442ea94788..06c57775367 100644
--- a/test/unit.fromasm.clamp
+++ b/test/unit.fromasm.clamp
@@ -31,6 +31,7 @@
  (export "conversions" (func $conversions))
  (export "switcher" (func $switcher))
  (export "frem" (func $frem))
+ (export "frem_float" (func $legalstub$frem_float))
  (export "big_uint_div_u" (func $big_uint_div_u))
  (export "fr" (func $legalstub$fr))
  (export "negZero" (func $negZero))
@@ -269,6 +270,14 @@
    (f64.const 1.2)
   )
  )
+ (func $frem_float (result f32)
+  (f32.demote/f64
+   (call $f64-rem
+    (f64.const 5.5)
+    (f64.const 1.2000000476837158)
+   )
+  )
+ )
  (func $i32u-div (param $0 i32) (param $1 i32) (result i32)
   (if (result i32)
    (get_local $1)
@@ -1241,6 +1250,11 @@
  (func $ii (param $0 i32) (result i32)
   (get_local $0)
  )
+ (func $legalstub$frem_float (result f64)
+  (f64.promote/f32
+   (call $frem_float)
+  )
+ )
  (func $legalstub$fr (param $0 f64)
   (call $fr
    (f32.demote/f64
diff --git a/test/unit.fromasm.clamp.no-opts b/test/unit.fromasm.clamp.no-opts
index 37456128f5d..393147603fd 100644
--- a/test/unit.fromasm.clamp.no-opts
+++ b/test/unit.fromasm.clamp.no-opts
@@ -38,6 +38,7 @@
  (export "conversions" (func $conversions))
  (export "switcher" (func $switcher))
  (export "frem" (func $frem))
+ (export "frem_float" (func $legalstub$frem_float))
  (export "big_uint_div_u" (func $big_uint_div_u))
  (export "fr" (func $legalstub$fr))
  (export "negZero" (func $negZero))
@@ -407,6 +408,20 @@
    )
   )
  )
+ (func $frem_float (result f32)
+  (return
+   (f32.demote/f64
+    (call $f64-rem
+     (f64.promote/f32
+      (f32.const 5.5)
+     )
+     (f64.promote/f32
+      (f32.const 1.2000000476837158)
+     )
+    )
+   )
+  )
+ )
  (func $i32u-div (param $0 i32) (param $1 i32) (result i32)
   (if (result i32)
    (i32.eqz
@@ -2030,6 +2045,11 @@
    (get_local $x)
   )
  )
+ (func $legalstub$frem_float (result f64)
+  (f64.promote/f32
+   (call $frem_float)
+  )
+ )
  (func $legalstub$fr (param $0 f64)
   (call $fr
    (f32.demote/f64
diff --git a/test/unit.fromasm.imprecise b/test/unit.fromasm.imprecise
index ea664d5f017..8ee0b073f59 100644
--- a/test/unit.fromasm.imprecise
+++ b/test/unit.fromasm.imprecise
@@ -30,6 +30,7 @@
  (export "conversions" (func $big_negative))
  (export "switcher" (func $switcher))
  (export "frem" (func $frem))
+ (export "frem_float" (func $legalstub$frem_float))
  (export "big_uint_div_u" (func $big_uint_div_u))
  (export "fr" (func $legalstub$fr))
  (export "negZero" (func $negZero))
@@ -226,6 +227,14 @@
    (f64.const 1.2)
   )
  )
+ (func $frem_float (result f32)
+  (f32.demote/f64
+   (call $f64-rem
+    (f64.const 5.5)
+    (f64.const 1.2000000476837158)
+   )
+  )
+ )
  (func $big_uint_div_u (result i32)
   (i32.const 2147483647)
  )
@@ -1190,6 +1199,11 @@
  (func $ii (param $0 i32) (result i32)
   (get_local $0)
  )
+ (func $legalstub$frem_float (result f64)
+  (f64.promote/f32
+   (call $frem_float)
+  )
+ )
  (func $legalstub$fr (param $0 f64)
   (call $fr
    (f32.demote/f64
diff --git a/test/unit.fromasm.imprecise.no-opts b/test/unit.fromasm.imprecise.no-opts
index 227cf5e793b..70eece97df4 100644
--- a/test/unit.fromasm.imprecise.no-opts
+++ b/test/unit.fromasm.imprecise.no-opts
@@ -38,6 +38,7 @@
  (export "conversions" (func $conversions))
  (export "switcher" (func $switcher))
  (export "frem" (func $frem))
+ (export "frem_float" (func $legalstub$frem_float))
  (export "big_uint_div_u" (func $big_uint_div_u))
  (export "fr" (func $legalstub$fr))
  (export "negZero" (func $negZero))
@@ -379,6 +380,20 @@
    )
   )
  )
+ (func $frem_float (result f32)
+  (return
+   (f32.demote/f64
+    (call $f64-rem
+     (f64.promote/f32
+      (f32.const 5.5)
+     )
+     (f64.promote/f32
+      (f32.const 1.2000000476837158)
+     )
+    )
+   )
+  )
+ )
  (func $big_uint_div_u (result i32)
   (local $x i32)
   (set_local $x
@@ -1990,6 +2005,11 @@
    (get_local $x)
   )
  )
+ (func $legalstub$frem_float (result f64)
+  (f64.promote/f32
+   (call $frem_float)
+  )
+ )
  (func $legalstub$fr (param $0 f64)
   (call $fr
    (f32.demote/f64
diff --git a/test/unit.fromasm.no-opts b/test/unit.fromasm.no-opts
index 878011cefd2..511e310a399 100644
--- a/test/unit.fromasm.no-opts
+++ b/test/unit.fromasm.no-opts
@@ -40,6 +40,7 @@
  (export "conversions" (func $conversions))
  (export "switcher" (func $switcher))
  (export "frem" (func $frem))
+ (export "frem_float" (func $legalstub$frem_float))
  (export "big_uint_div_u" (func $big_uint_div_u))
  (export "fr" (func $legalstub$fr))
  (export "negZero" (func $negZero))
@@ -383,6 +384,20 @@
    )
   )
  )
+ (func $frem_float (result f32)
+  (return
+   (f32.demote/f64
+    (call $f64-rem
+     (f64.promote/f32
+      (f32.const 5.5)
+     )
+     (f64.promote/f32
+      (f32.const 1.2000000476837158)
+     )
+    )
+   )
+  )
+ )
  (func $i32u-div (param $0 i32) (param $1 i32) (result i32)
   (if (result i32)
    (i32.eqz
@@ -2006,6 +2021,11 @@
    (get_local $x)
   )
  )
+ (func $legalstub$frem_float (result f64)
+  (f64.promote/f32
+   (call $frem_float)
+  )
+ )
  (func $legalstub$fr (param $0 f64)
   (call $fr
    (f32.demote/f64