fix crash in js optimizer loop variables pass on empty if blocks

3 files changed, 14 insertions, 3 deletions

diff --git a/tools/eliminator/asm-eliminator-test-output.js b/tools/eliminator/asm-eliminator-test-output.js
index b28fbd4a..5cc6238e 100644
--- a/tools/eliminator/asm-eliminator-test-output.js
+++ b/tools/eliminator/asm-eliminator-test-output.js
@@ -5121,4 +5121,9 @@ function tempDouble2($46, $14, $28, $42, $20, $32, $45) {
  HEAP32[$45 + 4 >> 2] = $_sroa_06_0_insert_insert$1;
  HEAP32[$45 + 8 >> 2] = $_sroa_06_0_insert_insert$1;
 }
+function watIf() {
+ while (1) {
+  if ($cmp38) {} else {}
+ }
+}
 
diff --git a/tools/eliminator/asm-eliminator-test.js b/tools/eliminator/asm-eliminator-test.js
index f90c3557..b33c6040 100644
--- a/tools/eliminator/asm-eliminator-test.js
+++ b/tools/eliminator/asm-eliminator-test.js
@@ -6851,5 +6851,11 @@ function tempDouble2($46, $14, $28, $42, $20, $32, $45) {
  HEAP32[$45 + 4 >> 2] = $_sroa_06_0_insert_insert$1;
  HEAP32[$45 + 8 >> 2] = $_sroa_06_0_insert_insert$1;
 }
-// EMSCRIPTEN_GENERATED_FUNCTIONS: ["asm", "__Z11printResultPiS_j", "_segment_holding", "__ZN5identC2EiPKcPci", "_vec2Length", "exc", "label", "confuusion", "tempDouble", "_org_apache_harmony_luni_util_NumberConverter_freeFormat__", "__ZN23b2EdgeAndPolygonContact8EvaluateEP10b2ManifoldRK11b2TransformS4_", "_java_nio_charset_Charset_forNameInternal___java_lang_String", "looop2", "looop3", "looop4", "looop5", "looop6", "looop7", "looop8", "multiloop", "multiloop2", "tempDouble2"]
+function watIf() {
+ while (1) {
+  if ($cmp38) {} else {
+  }
+ }
+}
+// EMSCRIPTEN_GENERATED_FUNCTIONS: ["asm", "__Z11printResultPiS_j", "_segment_holding", "__ZN5identC2EiPKcPci", "_vec2Length", "exc", "label", "confuusion", "tempDouble", "_org_apache_harmony_luni_util_NumberConverter_freeFormat__", "__ZN23b2EdgeAndPolygonContact8EvaluateEP10b2ManifoldRK11b2TransformS4_", "_java_nio_charset_Charset_forNameInternal___java_lang_String", "looop2", "looop3", "looop4", "looop5", "looop6", "looop7", "looop8", "multiloop", "multiloop2", "tempDouble2", "watIf"]
 
diff --git a/tools/js-optimizer.js b/tools/js-optimizer.js
index 67cd8066..7561abc8 100644
--- a/tools/js-optimizer.js
+++ b/tools/js-optimizer.js
@@ -2535,13 +2535,13 @@ function eliminate(ast, memSafe) {
           var ifTrue = last[2];
           var ifFalse = last[3];
           var flip = false;
-          if (ifFalse[1][0][0] == 'break') { // canonicalize break in the if
+          if (ifFalse[1][0] && ifFalse[1][0][0] == 'break') { // canonicalize break in the if
             var temp = ifFalse;
             ifFalse = ifTrue;
             ifTrue = temp;
             flip = true;
           }
-          if (ifTrue[1][0][0] == 'break') {
+          if (ifTrue[1][0] && ifTrue[1][0][0] == 'break') {
             var assigns = ifFalse[1];
             var loopers = [], helpers = [];
             for (var i = 0; i < assigns.length; i++) {