Add FOLD rule for FLOAT->NUM->FLOAT conversions.

2 files changed, 14 insertions, 3 deletions

diff --git a/src/buildvm_fold.c b/src/buildvm_fold.c
index 33a117d7..b43d2c48 100644
--- a/src/buildvm_fold.c
+++ b/src/buildvm_fold.c
@@ -111,13 +111,15 @@ static uint32_t nexttoken(char **pp, int allowlit, int allowany)
         if (!strcmp(ircall_names[i], p+7))
           return i;
     } else if (allowlit && !strncmp(p, "IRCONV_", 7)) {
-      for (i = 0; irt_names[i]; i++)
-        if (!strncmp(irt_names[i], p+7, 3) && p[10] == '_') {
+      for (i = 0; irt_names[i]; i++) {
+        const char *r = strchr(p+7, '_');
+        if (r && !strncmp(irt_names[i], p+7, r-(p+7))) {
           uint32_t j;
           for (j = 0; irt_names[j]; j++)
-            if (!strncmp(irt_names[j], p+11, 3))
+            if (!strcmp(irt_names[j], r+1))
               return (i << 5) + j;
         }
+      }
     } else if (allowlit && *p >= '0' && *p <= '9') {
       for (i = 0; *p >= '0' && *p <= '9'; p++)
         i = i*10 + (*p - '0');
diff --git a/src/lj_opt_fold.c b/src/lj_opt_fold.c
index edd376c9..44a55709 100644
--- a/src/lj_opt_fold.c
+++ b/src/lj_opt_fold.c
@@ -914,6 +914,15 @@ LJFOLDF(simplify_conv_int_i64)
   return NEXTFOLD;
 }
 
+LJFOLD(CONV CONV IRCONV_NUM_FLOAT)  /* _NUM */
+LJFOLDF(simplify_conv_flt_num)
+{
+  PHIBARRIER(fleft);
+  if ((fleft->op2 & IRCONV_SRCMASK) == IRT_NUM)
+    return fleft->op1;
+  return NEXTFOLD;
+}
+
 /* Shortcut TOBIT + IRT_NUM <- IRT_INT/IRT_U32 conversion. */
 LJFOLD(TOBIT CONV KNUM)
 LJFOLDF(simplify_tobit_conv)