Segregate the register iterations based on intType/floatType

[kunalspathak]

We noticed in #79544 (comment) and lately in #82731 that we should not iterate over all the register sets (specially do not iterate over float/SIMD if we know that there are no variables in the method). This will improve the TP performance.

Today, at multiple hot places, we iterate over all the registers.

for (regNumber reg = REG_FIRST; reg < ACTUAL_REG_COUNT; reg = REG_NEXT(reg))
{
 ...
}

Some other TP improvement potential:

• Avx512 extract most significant bits #82731 (comment) (Completed in Fixes #79187 Add MemoryMappedFile.CreateFromFile(SafeFileHandle) overload #83134)
• Avx512 extract most significant bits #82731 (comment)

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Issue Details

---

We noticed in #79544 (comment) and lately in #82731 that we should not iterate over all the register sets (specially do not iterate over float/SIMD if we know that there are no variables in the method). This will improve the TP performance.

Today, at multiple hot places, we iterate over all the registers.

for (regNumber reg = REG_FIRST; reg < ACTUAL_REG_COUNT; reg = REG_NEXT(reg))
{
 ...
}

Author:	kunalspathak
Assignees:	kunalspathak
Labels:	area-CodeGen-coreclr, untriaged
Milestone:	-