From: svenpanne@chromium.org <svenpanne@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Mon, 16 Sep 2013 13:51:14 +0000 (+0000)
Subject: In the case of shift amounts with two constants and if their sum is equal 32, then... 
X-Git-Tag: upstream/4.7.83~12483
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=8ed9b08e31854b6b1e8671ad73dccde75d40d352;p=platform%2Fupstream%2Fv8.git

In the case of shift amounts with two constants and if their sum is equal 32, then shift can also be replaced with bit rotate.

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/24095002

Patch from Bangfu Tao <bangfu.tao@samsung.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16735 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---

diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index bf51aa7..b567f61 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -7633,9 +7633,16 @@ HInstruction* HOptimizedGraphBuilder::BuildStringCharCodeAt(
 }
 
 
-// Checks if the given shift amounts have form: (sa) and (32 - sa).
+// Checks if the given shift amounts have following forms:
+// (N1) and (N2) with N1 + N2 = 32; (sa) and (32 - sa).
 static bool ShiftAmountsAllowReplaceByRotate(HValue* sa,
                                              HValue* const32_minus_sa) {
+  if (sa->IsConstant() && const32_minus_sa->IsConstant()) {
+    const HConstant* c1 = HConstant::cast(sa);
+    const HConstant* c2 = HConstant::cast(const32_minus_sa);
+    return c1->HasInteger32Value() && c2->HasInteger32Value() &&
+        (c1->Integer32Value() + c2->Integer32Value() == 32);
+  }
   if (!const32_minus_sa->IsSub()) return false;
   HSub* sub = HSub::cast(const32_minus_sa);
   if (sa != sub->right()) return false;
diff --git a/test/mjsunit/compiler/rotate.js b/test/mjsunit/compiler/rotate.js
index 14fe9da..2f4bc5a 100644
--- a/test/mjsunit/compiler/rotate.js
+++ b/test/mjsunit/compiler/rotate.js
@@ -222,3 +222,89 @@ for (var i = 0; i <= 100; i++) {
   assertEquals(1 << ((i % 32)), ROR4(1, i));
 }
 
+//---------------------------------------------------------
+// add test cases for constant operand
+//---------------------------------------------------------
+// constant operand: 20
+function ROR1_sa20(x) {
+  return (x >>> 20) | (x << 12);
+}
+
+function ROR2_sa20(x) {
+  return (x >>> 12) | (x << 20);
+}
+
+function ROR3_sa20(x, sa) {
+  return (x << 12) | (x >>> 20);
+}
+
+function ROR4_sa20(x) {
+  return (x << 20) | (x >>> 12);
+}
+
+// constant operand: 40
+function ROR1_sa40(x) {
+  return (x >>> 40) | (x << -8);
+}
+
+function ROR2_sa40(x) {
+  return (x >>> -8) | (x << 40);
+}
+
+function ROR3_sa40(x, sa) {
+  return (x << -8) | (x >>> 40);
+}
+
+function ROR4_sa40(x) {
+  return (x << 40) | (x >>> -8);
+}
+
+// ROR1_sa20
+assertEquals(ROR1(0x0000FFFF, 20), ROR1_sa20(0x0000FFFF));
+assertEquals(ROR1(0x0000FFFF, 20), ROR1_sa20(0x0000FFFF));
+%OptimizeFunctionOnNextCall(ROR1_sa20);
+assertEquals(ROR1(0x0000FFFF, 20), ROR1_sa20(0x0000FFFF));
+
+// ROR1_sa40
+assertEquals(ROR1(0x0000FFFF, 40), ROR1_sa40(0x0000FFFF));
+assertEquals(ROR1(0x0000FFFF, 40), ROR1_sa40(0x0000FFFF));
+%OptimizeFunctionOnNextCall(ROR1_sa40);
+assertEquals(ROR1(0x0000FFFF, 40), ROR1_sa40(0x0000FFFF));
+
+// ROR2_sa20
+assertEquals(ROR2(0xFFFFFFFF, 20), ROR2_sa20(0xFFFFFFFF));
+assertEquals(ROR2(0xFFFFFFFF, 20), ROR2_sa20(0xFFFFFFFF));
+%OptimizeFunctionOnNextCall(ROR2_sa20);
+assertEquals(ROR2(0xFFFFFFFF, 20), ROR2_sa20(0xFFFFFFFF));
+
+// ROR2_sa40
+assertEquals(ROR2(0x0000FFFF, 40), ROR2_sa40(0x0000FFFF));
+assertEquals(ROR2(0x0000FFFF, 40), ROR2_sa40(0x0000FFFF));
+%OptimizeFunctionOnNextCall(ROR2_sa40);
+assertEquals(ROR2(0x0000FFFF, 40), ROR2_sa40(0x0000FFFF));
+
+// ROR3_sa20
+assertEquals(ROR3(0x0000FFFF, 20), ROR3_sa20(0x0000FFFF));
+assertEquals(ROR3(0x0000FFFF, 20), ROR3_sa20(0x0000FFFF));
+%OptimizeFunctionOnNextCall(ROR3_sa20);
+assertEquals(ROR3(0x0000FFFF, 20), ROR3_sa20(0x0000FFFF));
+
+// ROR3_sa40
+assertEquals(ROR3(0x0000FFFF, 40), ROR3_sa40(0x0000FFFF));
+assertEquals(ROR3(0x0000FFFF, 40), ROR3_sa40(0x0000FFFF));
+%OptimizeFunctionOnNextCall(ROR3_sa40);
+assertEquals(ROR3(0x0000FFFF, 40), ROR3_sa40(0x0000FFFF));
+
+// ROR4_sa20
+assertEquals(ROR4(0x0000FFFF, 20), ROR4_sa20(0x0000FFFF));
+assertEquals(ROR4(0x0000FFFF, 20), ROR4_sa20(0x0000FFFF));
+%OptimizeFunctionOnNextCall(ROR4_sa20);
+assertEquals(ROR4(0x0000FFFF, 20), ROR4_sa20(0x0000FFFF));
+
+// ROR4_sa40
+assertEquals(ROR4(0xFFFFFFFF, 40), ROR4_sa40(0xFFFFFFFF));
+assertEquals(ROR4(0xFFFFFFFF, 40), ROR4_sa40(0xFFFFFFFF));
+%OptimizeFunctionOnNextCall(ROR4_sa40);
+assertEquals(ROR4(0xFFFFFFFF, 40), ROR4_sa40(0xFFFFFFFF));
+
+