Reverting because mis-compiles:
- https://github.com/llvm/llvm-project/pull/131837
- https://github.com/llvm/llvm-project/pull/146320
- https://github.com/llvm/llvm-project/pull/146337

The insertion point of COPY isn't always optimal and could eventually
lead to a worse block layout, see the regression test in the first
commit.

This change affects many architectures but the amount of total
instructions in the test cases seems too be slightly lower.

instructionWaitsForSGPRWrites function covers ALL SALU instructions,
including those like s_waitcnt that don't read from sgpr. This results
in removing delay_alu instructions in cases like VALU->SGPR->VALU, which
results in performance regression. Change modifies the function so that
it checks if instruction also reads a sgpr.

This is a NFC patch.

This patch run a bulk update on CodeGen tests that are impacted by the
true16 features. This patch applies:
1. duplicate GFX11plus runlines and apply them with
"+mattr=+real-true16" and "+mattr=-real-true16"
2. update the test with the update script

For some GISEL runlines, the current CodeGen do not fully support the
true16 version. Still update the runlines, but comment out the failing
one, and added a "FIXME-TRUE16" comment to that test for easier
tracking. These test will be fixed in the following patches.

This is in a transition state that we support both
"+real-true16/-real-true16" in our code base. We plan to move to
"+real-true16" as default, and finally remove "-real-true16" mode and
test lines.

This patch addresses the signed/zero extension of poison by using a
poison value of the extended type instead of a constant zero of the
extended type.

This reverts commit f12078e72601e7c03e5d66afab034313caf8f791.

Breaks `check-llvm`, see comments on https://github.com/llvm/llvm-project/pull/122741

The PR will fix the issue
https://github.com/llvm/llvm-project/issues/122728

This patch addresses the signed/zero extension of poison by using a
poison value of the extended type instead of a constant zero of the
extended type.

Re-apply https://github.com/llvm/llvm-project/pull/130577

Which is reverted in https://github.com/llvm/llvm-project/pull/133880

The old application failed in address sanitizer due to
`tryNarrowMathIfNoOverflow` was called after `I.eraseFromParent();` in
`AMDGPUCodeGenPrepareImpl::visitBinaryOperator`, it create a use after
free failure.

To fix this, `tryNarrowMathIfNoOverflow` will be called before and
directly return if `tryNarrowMathIfNoOverflow` result in true.

Reverts llvm/llvm-project#130577

For Add, Sub, Mul with Int64 type, if profitable, then do:
1. Trunc operands to Int32 type
2. Apply 32 bit Add/Sub/Mul
3. Zext to Int64 type