[optimizing] Improve 32 bit long shift by 1.
Also change FOO << 1 to FOO+FOO in the instruction simplifier. This is
an architecture independent simplification, which helps 'long << 1' for
32 bit architectures.
Generate an add/adc for long << 1 in x86, in case something is generated
after the simplifier.
Add test cases for the simplification.
Change-Id: I0d512331ef13cc4ccf10c80f11c370a10ed02294
Signed-off-by: Mark Mendell <mark.p.mendell@intel.com>
diff --git a/compiler/optimizing/instruction_simplifier.cc b/compiler/optimizing/instruction_simplifier.cc
index e79d4f4..46fad17 100644
--- a/compiler/optimizing/instruction_simplifier.cc
+++ b/compiler/optimizing/instruction_simplifier.cc
@@ -137,13 +137,25 @@
HConstant* input_cst = instruction->GetConstantRight();
HInstruction* input_other = instruction->GetLeastConstantLeft();
- if ((input_cst != nullptr) && input_cst->IsZero()) {
- // Replace code looking like
- // SHL dst, src, 0
- // with
- // src
- instruction->ReplaceWith(input_other);
- instruction->GetBlock()->RemoveInstruction(instruction);
+ if (input_cst != nullptr) {
+ if (input_cst->IsZero()) {
+ // Replace code looking like
+ // SHL dst, src, 0
+ // with
+ // src
+ instruction->ReplaceWith(input_other);
+ instruction->GetBlock()->RemoveInstruction(instruction);
+ } else if (instruction->IsShl() && input_cst->IsOne()) {
+ // Replace Shl looking like
+ // SHL dst, src, 1
+ // with
+ // ADD dst, src, src
+ HAdd *add = new(GetGraph()->GetArena()) HAdd(instruction->GetType(),
+ input_other,
+ input_other);
+ instruction->GetBlock()->ReplaceAndRemoveInstructionWith(instruction, add);
+ RecordSimplification();
+ }
}
}