Do not use repeated subtractions in mod-i, it hurts performance in general.

src/ia32/lithium-codegen-ia32.cc

Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index 91549a274a7d4e361d423c655d204f607c4fab69..4318f31689916634f23032167ece94f30d05f8be 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -1234,7 +1234,7 @@ void LCodeGen::DoModI(LModI* instr) {
     __ and_(dividend, divisor - 1);
     __ bind(&done);
   } else {
-    Label done, remainder_eq_dividend, slow, do_subtraction, both_positive;
+    Label done, remainder_eq_dividend, slow, both_positive;
     Register left_reg = ToRegister(instr->left());
     Register right_reg = ToRegister(instr->right());
     Register result_reg = ToRegister(instr->result());
@@ -1270,23 +1270,10 @@ void LCodeGen::DoModI(LModI* instr) {
     __ mov(scratch, right_reg);
     __ sub(Operand(scratch), Immediate(1));
     __ test(scratch, Operand(right_reg));
-    __ j(not_zero, &do_subtraction, Label::kNear);
+    __ j(not_zero, &slow, Label::kNear);
     __ and_(left_reg, Operand(scratch));
     __ jmp(&remainder_eq_dividend, Label::kNear);
 
-    __ bind(&do_subtraction);
-    const int kUnfolds = 3;
-    // Try a few subtractions of the dividend.
-    __ mov(scratch, left_reg);
-    for (int i = 0; i < kUnfolds; i++) {
-      // Reduce the dividend by the divisor.
-      __ sub(left_reg, Operand(right_reg));
-      // Check if the dividend is less than the divisor.
-      __ cmp(left_reg, Operand(right_reg));
-      __ j(less, &remainder_eq_dividend, Label::kNear);
-    }
-    __ mov(left_reg, scratch);
-
     // Slow case, using idiv instruction.
     __ bind(&slow);