Implement ARM32 switch lowering.
A naive implementation of switch lowering using sequential tests for each of the cases.
BUG= none
TEST=switch-opt.ll
R=jvoung@chromium.org
Review URL: https://codereview.chromium.org/1213593002.
diff --git a/src/IceTargetLoweringARM32.cpp b/src/IceTargetLoweringARM32.cpp
index 4797683..b1081b3 100644
--- a/src/IceTargetLoweringARM32.cpp
+++ b/src/IceTargetLoweringARM32.cpp
@@ -2037,8 +2037,36 @@
}
void TargetARM32::lowerSwitch(const InstSwitch *Inst) {
- (void)Inst;
- UnimplementedError(Func->getContext()->getFlags());
+ // This implements the most naive possible lowering.
+ // cmp a,val[0]; jeq label[0]; cmp a,val[1]; jeq label[1]; ... jmp default
+ Operand *Src0 = Inst->getComparison();
+ SizeT NumCases = Inst->getNumCases();
+ if (Src0->getType() == IceType_i64) {
+ // TODO(jvoung): handle and test undef for Src0
+ Variable *Src0Lo = legalizeToVar(loOperand(Src0));
+ Variable *Src0Hi = legalizeToVar(hiOperand(Src0));
+ for (SizeT I = 0; I < NumCases; ++I) {
+ Operand *ValueLo = Ctx->getConstantInt32(Inst->getValue(I));
+ Operand *ValueHi = Ctx->getConstantInt32(Inst->getValue(I) >> 32);
+ ValueLo = legalize(ValueLo, Legal_Reg | Legal_Flex);
+ ValueHi = legalize(ValueHi, Legal_Reg | Legal_Flex);
+ _cmp(Src0Lo, ValueLo);
+ _cmp(Src0Hi, ValueHi, CondARM32::EQ);
+ _br(Inst->getLabel(I), CondARM32::EQ);
+ }
+ _br(Inst->getLabelDefault());
+ return;
+ }
+
+ // 32 bit integer
+ Variable *Src0Var = legalizeToVar(Src0);
+ for (SizeT I = 0; I < NumCases; ++I) {
+ Operand *Value = Ctx->getConstantInt32(Inst->getValue(I));
+ Value = legalize(Value, Legal_Reg | Legal_Flex);
+ _cmp(Src0Var, Value);
+ _br(Inst->getLabel(I), CondARM32::EQ);
+ }
+ _br(Inst->getLabelDefault());
}
void TargetARM32::lowerUnreachable(const InstUnreachable * /*Inst*/) {
