X87: Fixed flooring division by a power of 2, once again...

src/x87/lithium-codegen-x87.cc

Index: src/x87/lithium-codegen-x87.cc
diff --git a/src/x87/lithium-codegen-x87.cc b/src/x87/lithium-codegen-x87.cc
index 1e9168d4bb5c7b58c6dc310dc661877f1856b127..dab87688a3f870a8518a29d8b60724d8ab35200c 100644
--- a/src/x87/lithium-codegen-x87.cc
+++ b/src/x87/lithium-codegen-x87.cc
@@ -1546,14 +1546,17 @@ void LCodeGen::DoFlooringDivByPowerOf2I(LFlooringDivByPowerOf2I* instr) {
     DeoptimizeIf(zero, instr->environment());
   }
 
-  if (!instr->hydrogen()->CheckFlag(HValue::kLeftCanBeMinInt)) {
-    __ sar(dividend, shift);
+  // Dividing by -1 is basically negation, unless we overflow.
+  if (divisor == -1) {
+    if (instr->hydrogen()->CheckFlag(HValue::kLeftCanBeMinInt)) {
+      DeoptimizeIf(overflow, instr->environment());
+    }
     return;
   }
 
-  // Dividing by -1 is basically negation, unless we overflow.
-  if (divisor == -1) {
-    DeoptimizeIf(overflow, instr->environment());
+  // If the negation could not overflow, simply shifting is OK.
+  if (!instr->hydrogen()->CheckFlag(HValue::kLeftCanBeMinInt)) {
+    __ sar(dividend, shift);
     return;
   }