Fix unreached during dump on amd64 Unix.

[sandreenko]

To repro the issue run the following with JitDump enabled:

 struct SMultiRegPromotedMatching
{
long l1;
long l2;
}
[MethodImpl(MethodImplOptions.NoInlining)]
static SMultiRegPromotedMatching Return1(SMultiRegPromotedMatching s)
{
return s;
}

s is passed using 2 regs, so its type is VLT_REG_REG.

[sandreenko]

PTAL @dotnet/jit-contrib, it is a one line change to fix JitDump issue.

[kunalspathak]

LGTM

[BruceForstall]

The declaration of VLT_REG_REG says:

 // VLT_REG_REG -- TYP_LONG with both uint32_ts enregistred
// eg. RBM_EAXEDX

which doesn't correspond to your case. In fact, it only seems to be set under !TARGET_64BIT... unless I'm behind?

[sandreenko]

The declaration of VLT_REG_REG says: TYP_LONG with both uint32_ts enregistred

Looks outdated, that is how we get it on x64 Unix:

void CodeGen::genFnProlog()->
void CodeGen::psiBegProlog()->
void CodeGen::psiBegProlog()->
void CodeGenInterface::siVarLoc::storeVariableInRegisters(regNumber reg, regNumber otherReg)

runtime/src/coreclr/jit/scopeinfo.cpp

Line 1585 in 94f3355

varLocation.storeVariableInRegisters(regNum, otherRegNum);

runtime/src/coreclr/jit/scopeinfo.cpp

Lines 165 to 170 in 94f3355

	// Two register are used
	vlType = VLT_REG_REG;
	vlRegReg.vlrrReg1 = reg;
	vlRegReg.vlrrReg2 = otherReg;
	}
	}

which doesn't correspond to your case. In fact, it only seems to be set under !TARGET_64BIT... unless I'm behind?

where do you see this?

Let me know if you want the comment to be updated.

[BruceForstall]

I was looking at CodeGenInterface::siVarLoc::siFillRegisterVarLoc; I missed the one you point out.

Don't worry about updating the comment now.

However, I'm curious if the debugger actually works with this...