PPC/s390: [Compiler] Use conditional move / select to generate poison mask.

Port 66870070

Original Commit Message:

    Replace bitwise arithmetic with conditional move / select instructions
    on ia32, x64, Arm and Arm64. In local tests this improves --noopt Ignition
    performance by between 2-5%.

R=rmcilroy@chromium.org, joransiu@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=chromium:798964
LOG=N

Change-Id: I3cb65bdf2cf48df30e97b8a12966636fa6aca5ec
Reviewed-on: https://chromium-review.googlesource.com/939852
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#51658}

src/compiler/ppc/code-generator-ppc.cc

@@ -844,18 +844,11 @@ void CodeGenerator::GenerateSpeculationPoison() {
 
   // Calculate a mask which has all bits set in the normal case, but has all
   // bits cleared if we are speculatively executing the wrong PC.
-  //    difference = (current - expected) | (expected - current)
-  //    poison = ~(difference >> (kBitsPerPointer - 1))
-  __ mr(kSpeculationPoisonRegister, scratch);
-  __ sub(kSpeculationPoisonRegister, kSpeculationPoisonRegister,
-         kJavaScriptCallCodeStartRegister);
-  __ sub(kJavaScriptCallCodeStartRegister, kJavaScriptCallCodeStartRegister,
-         scratch);
-  __ orx(kSpeculationPoisonRegister, kSpeculationPoisonRegister,
-         kJavaScriptCallCodeStartRegister);
-  __ ShiftRightArithImm(kSpeculationPoisonRegister, kSpeculationPoisonRegister,
-                        kBitsPerPointer - 1);
-  __ notx(kSpeculationPoisonRegister, kSpeculationPoisonRegister);
+  __ cmp(kJavaScriptCallCodeStartRegister, scratch);
+  __ li(scratch, Operand::Zero());
+  __ notx(kSpeculationPoisonRegister, scratch);
+  __ isel(eq, kSpeculationPoisonRegister,
+          kSpeculationPoisonRegister, scratch);
 }
 
 void CodeGenerator::AssembleRegisterArgumentPoisoning() {

src/compiler/s390/code-generator-s390.cc

@@ -1084,18 +1084,10 @@ void CodeGenerator::GenerateSpeculationPoison() {
 
   // Calculate a mask which has all bits set in the normal case, but has all
   // bits cleared if we are speculatively executing the wrong PC.
-  //    difference = (current - expected) | (expected - current)
-  //    poison = ~(difference >> (kBitsPerPointer - 1))
-  __ LoadRR(kSpeculationPoisonRegister, scratch);
-  __ SubP(kSpeculationPoisonRegister, kSpeculationPoisonRegister,
-          kJavaScriptCallCodeStartRegister);
-  __ SubP(kJavaScriptCallCodeStartRegister, kJavaScriptCallCodeStartRegister,
-          scratch);
-  __ OrP(kSpeculationPoisonRegister, kSpeculationPoisonRegister,
-         kJavaScriptCallCodeStartRegister);
-  __ ShiftRightArithP(kSpeculationPoisonRegister, kSpeculationPoisonRegister,
-                      Operand(kBitsPerPointer - 1));
-  __ NotP(kSpeculationPoisonRegister, kSpeculationPoisonRegister);
+  __ LoadImmP(kSpeculationPoisonRegister, Operand::Zero());
+  __ LoadImmP(r0, Operand(-1));
+  __ CmpP(kJavaScriptCallCodeStartRegister, scratch);
+  __ LoadOnConditionP(eq, kSpeculationPoisonRegister, r0);
 }
 
 void CodeGenerator::AssembleRegisterArgumentPoisoning() {