Set this on any source level floating-point type argument,
return value, call return or outgoing parameter which is lowered
to a valid IR type for the attribute. Currently this isn't
applied to emitted intrinsics since those don't go through
ABI code.

The conditions for which Clang emits the `unsafe-fp-math` function
attribute has been modified as part of
`84a9ec2ff1ee97fd7e8ed988f5e7b197aab84a7`.
In the backend code generators `"unsafe-fp-math"="true"` enable floating
point contraction for the whole function.
The intent of the change in `84a9ec2ff1ee97fd7e8ed988f5e7b197aab84a7`
was to prevent backend code generators performing contractions when that
is not expected.
However the change is inaccurate and incomplete because it allows
`unsafe-fp-math` to be set also when only in-statement contraction is
allowed.

Consider the following example
```
float foo(float a, float b, float c) {
  float tmp = a * b;
  return tmp + c;
}
```
and compile it with the command line
```
clang -fno-math-errno -funsafe-math-optimizations -ffp-contract=on \
  -O2 -mavx512f -S -o -
```
The resulting assembly has a `vfmadd213ss` instruction which corresponds
to a fused multiply-add. From the user perspective there shouldn't be
any contraction because the multiplication and the addition are not in
the same statement.

The optimized IR is:
```
define float @test(float noundef %a, float noundef %b, float noundef %c) #0 {
  %mul = fmul reassoc nsz arcp afn float %b, %a
  %add = fadd reassoc nsz arcp afn float %mul, %c
  ret float %add
}

attributes #0 = {
  [...]
  "no-signed-zeros-fp-math"="true"
  "no-trapping-math"="true"
  [...]
  "unsafe-fp-math"="true"
}
```
The `"unsafe-fp-math"="true"` function attribute allows the backend code
generator to perform `(fadd (fmul a, b), c) -> (fmadd a, b, c)`.

In the current IR representation there is no way to determine the
statement boundaries from the original source code.
Because of this for in-statement only contraction the generated IR
doesn't have instructions with the `contract` fast-math flag and
`llvm.fmuladd` is being used to represent contractions opportunities
that occur within a single statement.
Therefore `"unsafe-fp-math"="true"` can only be emitted when contraction
across statements is allowed.

Moreover the change in `84a9ec2ff1ee97fd7e8ed988f5e7b197aab84a7` doesn't
take into account that the floating point math function attributes can
be refined during IR code generation of a function to handle the cases
where the floating point math options are modified within a compound
statement via pragmas (see `CGFPOptionsRAII`).
For consistency `unsafe-fp-math` needs to be disabled if the contraction
mode for any scope/operation is not `fast`.
Similarly for consistency reason the initialization of `UnsafeFPMath` of
in `TargetOptions` for the backend code generation should take into
account the contraction mode as well.

Reviewed By: zahiraam

Differential Revision: https://reviews.llvm.org/D136786

Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I modified clang by renaming `enable_noundef_analysis` flag to `disable-noundef-analysis` and turning it off by default.

Test updates are made as a separate patch: D108453

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D105169

This reverts commit aacfbb953eb705af2ecfeb95a6262818fa85dd92.

Revert "Fix lit test failures in CodeGenCoroutines"

This reverts commit 63fff0f5bffe20fa2c84a45a41161afa0043cb34.

Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I modified clang by renaming `enable_noundef_analysis` flag to `disable-noundef-analysis` and turning it off by default.

Test updates are made as a separate patch: D108453

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D105169

[Clang/Test]: Rename enable_noundef_analysis to disable-noundef-analysis and turn it off by default (2)

This patch updates test files after D105169.
Autogenerated test codes are changed by `utils/update_cc_test_checks.py,` and non-autogenerated test codes are changed as follows:

(1) I wrote a python script that (partially) updates the tests using regex: {F18594904} The script is not perfect, but I believe it gives hints about which patterns are updated to have `noundef` attached.

(2) The remaining tests are updated manually.

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D108453

Resolve lit failures in clang after 8ca4b3e's land

Fix lit test failures in clang-ppc* and clang-x64-windows-msvc

Fix missing failures in clang-ppc64be* and retry fixing clang-x64-windows-msvc

Fix internal_clone(aarch64) inline assembly

This reverts commit 7584ef766a7219b6ee5a400637206d26e0fa98ac.

Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I modified clang by renaming `enable_noundef_analysis` flag to `disable-noundef-analysis` and turning it off by default.

Test updates are made as a separate patch: D108453

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D105169

This reverts the following commits:
37ca7a795b277c20c02a218bf44052278c03344b
9aa6c72b92b6c89cc6d23b693257df9af7de2d15
705387c5074bcca36d626882462ebbc2bcc3bed4
8ca4b3ef19fe82d7ad6a6e1515317dcc01b41515
80dba72a669b5416e97a42fd2c2a7bc5a6d3f44a

This patch updates test files after D105169.
Autogenerated test codes are changed by `utils/update_cc_test_checks.py,` and non-autogenerated test codes are changed as follows:

(1) I wrote a python script that (partially) updates the tests using regex: {F18594904} The script is not perfect, but I believe it gives hints about which patterns are updated to have `noundef` attached.

(2) The remaining tests are updated manually.

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D108453

For a default visibility external linkage definition, dso_local is set for ELF
-fno-pic/-fpie and COFF and Mach-O. Since default clang -cc1 for ELF is similar
to -fpic ("PIC Level" is not set), this nuance causes unneeded binary format differences.

To make emitted IR similar, ELF -cc1 -fpic will default to -fno-semantic-interposition,
which sets dso_local for default visibility external linkage definitions.

To make this flip smooth and enable future (dso_local as definition default),
this patch replaces (function) `define ` with `define{{.*}} `,
(variable/constant/alias) `= ` with `={{.*}} `, or inserts appropriate `{{.*}} `.