Fix pow() optimization inconsistencies.

src/lj_opt_fold.c

@@ -1143,33 +1143,6 @@ LJFOLDF(simplify_numpow_xkint)
   return ref;
 }
 
-LJFOLD(POW any KNUM)
-LJFOLDF(simplify_numpow_xknum)
-{
-  if (knumright == 0.5)  /* x ^ 0.5 ==> sqrt(x) */
-    return emitir(IRTN(IR_FPMATH), fins->op1, IRFPM_SQRT);
-  return NEXTFOLD;
-}
-
-LJFOLD(POW KNUM any)
-LJFOLDF(simplify_numpow_kx)
-{
-  lua_Number n = knumleft;
-  if (n == 2.0 && irt_isint(fright->t)) {  /* 2.0 ^ i ==> ldexp(1.0, i) */
-#if LJ_TARGET_X86ORX64
-    /* Different IR_LDEXP calling convention on x86/x64 requires conversion. */
-    fins->o = IR_CONV;
-    fins->op1 = fins->op2;
-    fins->op2 = IRCONV_NUM_INT;
-    fins->op2 = (IRRef1)lj_opt_fold(J);
-#endif
-    fins->op1 = (IRRef1)lj_ir_knum_one(J);
-    fins->o = IR_LDEXP;
-    return RETRYFOLD;
-  }
-  return NEXTFOLD;
-}
-
 /* -- Simplify conversions ------------------------------------------------ */
 
 LJFOLD(CONV CONV IRCONV_NUM_INT)  /* _NUM */