Add bool value types to type inference.

pkg/compiler/lib/src/ssa/optimize.dart

Index: pkg/compiler/lib/src/ssa/optimize.dart
diff --git a/pkg/compiler/lib/src/ssa/optimize.dart b/pkg/compiler/lib/src/ssa/optimize.dart
index cb0318362417e0d38d9acea196e443eadf794362..25796f6a2c20da236f0455d97918a91d38e15cbc 100644
--- a/pkg/compiler/lib/src/ssa/optimize.dart
+++ b/pkg/compiler/lib/src/ssa/optimize.dart
@@ -1306,6 +1306,13 @@ class SsaLiveBlockAnalyzer extends HBaseVisitor {
       } else {
         markBlockLive(instruction.elseBlock);
       }
+    } else if (condition.isValue()) {
+      ValueTypeMask valueType = condition.instructionType;

[sra1, 2015/09/29 01:02:05]

I don't think we should it like this.

We should rather replace values that are inferred to a constant bool with a
HConstant in SsaInstructionSimplifier.  That will (1) sever dependencies and (2)
enable constant folding.

E.g.

    r = massiveFnReturningArgument(false);
    if (r != null)
      print(r);

becomes

    massiveFnReturningArgument(false);
    P.printLine("false");


1. Add helper method to SsaInstructionSimplifier to check and replace all uses
of an instruction with the appropriate HConstant if appropriate.
2. Add SsaInstructionSimplifier.visitParameterValue and call the helper to
convert values coming in from call site arguments.
3. Add calls at a few of the visitInvokeXXX methods too convert values returned
from call sites.

[Harry Terkelsen, 2015/09/29 01:09:53]

I wanted to do this but I didn't know how to convert to an HConstant while also
doing calls for the effects. What is the correct way?

[Harry Terkelsen, 2015/09/29 01:16:34]

Oops, replied before fully reading your comment. I'll implement this

+      if (valueType.value == true) {
+        markBlockLive(instruction.thenBlock);
+      } else {
+        markBlockLive(instruction.elseBlock);
+      }
     } else {
       visitControlFlow(instruction);
     }