commit a66784b09f10d847b49bc878f10c45690e212f0b
author Shalini Salomi Bodapati <shalini.salomi.bodapati@intel.com> Tue Nov 06 13:05:44 2018 +0530
committer Shalini Salomi Bodapati <shalini.salomi.bodapati@intel.com> Mon Nov 12 21:09:32 2018 +0530
tree a18ee4ec39a44256223b9f756159bfd535ddfde3
parent fe59955fc41e277bf1c60378202ba785abb1e4a8

Optimize mod power 2 for x86

Test: 411-checker-hdiv-hrem-pow2, test.py --host

Change-Id: I9334a3eb2cb50df439b56c0161379fef46e58603
Signed-off-by: Shalini Salomi Bodapati <shalini.salomi.bodapati@intel.com>

compiler/optimizing/code_generator_x86.cc

diff --git a/compiler/optimizing/code_generator_x86.cc b/compiler/optimizing/code_generator_x86.cc
index 9f34a51..7745f64 100644
--- a/compiler/optimizing/code_generator_x86.cc
+++ b/compiler/optimizing/code_generator_x86.cc
@@ -3497,6 +3497,27 @@
   }
 }
 
+void InstructionCodeGeneratorX86::RemByPowerOfTwo(HRem* instruction) {
+  LocationSummary* locations = instruction->GetLocations();
+  Location second = locations->InAt(1);
+
+  Register out = locations->Out().AsRegister<Register>();
+  Register numerator = locations->InAt(0).AsRegister<Register>();
+
+  int32_t imm = Int64FromConstant(second.GetConstant());
+  DCHECK(IsPowerOfTwo(AbsOrMin(imm)));
+  uint32_t abs_imm = static_cast<uint32_t>(AbsOrMin(imm));
+
+  Register tmp = locations->GetTemp(0).AsRegister<Register>();
+  NearLabel done;
+  __ movl(out, numerator);
+  __ andl(out, Immediate(abs_imm-1));
+  __ j(Condition::kZero, &done);
+  __ leal(tmp, Address(out, static_cast<int32_t>(~(abs_imm-1))));
+  __ testl(numerator, numerator);
+  __ cmovl(Condition::kLess, out, tmp);
+  __ Bind(&done);
+}
 
 void InstructionCodeGeneratorX86::DivByPowerOfTwo(HDiv* instruction) {
   LocationSummary* locations = instruction->GetLocations();
@@ -3610,8 +3631,12 @@
           // Do not generate anything for 0. DivZeroCheck would forbid any generated code.
         } else if (imm == 1 || imm == -1) {
           DivRemOneOrMinusOne(instruction);
-        } else if (is_div && IsPowerOfTwo(AbsOrMin(imm))) {
-          DivByPowerOfTwo(instruction->AsDiv());
+        } else if (IsPowerOfTwo(AbsOrMin(imm))) {
+          if (is_div) {
+            DivByPowerOfTwo(instruction->AsDiv());
+          } else {
+            RemByPowerOfTwo(instruction->AsRem());
+          }
         } else {
           DCHECK(imm <= -2 || imm >= 2);
           GenerateDivRemWithAnyConstant(instruction);