Support non-deoptimizing version of UnboxInt32 for integer definitions.

If range analysis infered that integer definition is within Int32 range then it is guaranteed to be either Smi or Mint.

BUG=http://dartbug.com/21763
R=fschneider@google.com

Review URL: https://codereview.chromium.org//770303002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@42065 260f80e4-7a28-3924-810f-c04153c831b5

runtime/vm/intermediate_language.cc

@@ -1202,6 +1202,10 @@ bool UnboxInt32Instr::CanDeoptimize() const {
     return !is_truncating() &&
         !RangeUtils::Fits(value()->definition()->range(),
                           RangeBoundary::kRangeBoundaryInt32);
+  } else if ((kSmiBits < 32) && value()->Type()->IsInt()) {
+    // Note: we don't support truncation of Bigint values.
+    return !RangeUtils::Fits(value()->definition()->range(),
+                             RangeBoundary::kRangeBoundaryInt32);
   } else {
     return true;
   }

runtime/vm/intermediate_language_arm.cc

@@ -3986,6 +3986,11 @@ void UnboxInteger32Instr::EmitNativeCode(FlowGraphCompiler* compiler) {
     __ SmiUntag(out, value);
   } else if (value_cid == kMintCid) {
     LoadInt32FromMint(compiler, value, out, temp, out_of_range);
+  } else if (!CanDeoptimize()) {
+    Label done;
+    __ SmiUntag(out, value, &done);
+    LoadInt32FromMint(compiler, value, out, kNoRegister, NULL);
+    __ Bind(&done);
   } else {
     Label done;
     __ SmiUntag(out, value, &done);

runtime/vm/intermediate_language_ia32.cc

@@ -3673,6 +3673,13 @@ void UnboxInteger32Instr::EmitNativeCode(FlowGraphCompiler* compiler) {
                       FieldAddress(value, hi_offset),
                       temp,
                       out_of_range);
+  } else if (!CanDeoptimize()) {
+    ASSERT(value == result);
+    Label done;
+    __ SmiUntag(value);
+    __ j(NOT_CARRY, &done);
+    __ movl(value, Address(value, TIMES_2, lo_offset));
+    __ Bind(&done);
   } else {
     ASSERT(value == result);
     Label done;

runtime/vm/intermediate_language_mips.cc

@@ -3347,6 +3347,13 @@ void UnboxInteger32Instr::EmitNativeCode(FlowGraphCompiler* compiler) {
     __ SmiUntag(out, value);
   } else if (value_cid == kMintCid) {
     LoadInt32FromMint(compiler, value, out, out_of_range);
+  } else if (!CanDeoptimize()) {
+    Label done;
+    __ SmiUntag(out, value);
+    __ andi(CMPRES1, value, Immediate(kSmiTagMask));
+    __ beq(CMPRES1, ZR, &done);
+    LoadInt32FromMint(compiler, value, out, NULL);
+    __ Bind(&done);
   } else {
     Label done;
     __ SmiUntag(out, value);