[llvm] [Intrinsics][PreISelInstrinsicLowering] llvm.memcpy.inline length no longer needs to be constant (PR #98281)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `premerge-monolithic-linux` running on `premerge-linux-1` while building `llvm` at step 7 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/153/builds/3111

Here is the relevant piece of the build log for the reference:
```
Step 7 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'MLIR :: Target/LLVMIR/llvmir-intrinsics.mlir' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
/build/buildbot/premerge-monolithic-linux/build/bin/mlir-translate -mlir-to-llvmir /build/buildbot/premerge-monolithic-linux/llvm-project/mlir/test/Target/LLVMIR/llvmir-intrinsics.mlir | /build/buildbot/premerge-monolithic-linux/build/bin/FileCheck /build/buildbot/premerge-monolithic-linux/llvm-project/mlir/test/Target/LLVMIR/llvmir-intrinsics.mlir
# executed command: /build/buildbot/premerge-monolithic-linux/build/bin/mlir-translate -mlir-to-llvmir /build/buildbot/premerge-monolithic-linux/llvm-project/mlir/test/Target/LLVMIR/llvmir-intrinsics.mlir
# note: command had no output on stdout or stderr
# executed command: /build/buildbot/premerge-monolithic-linux/build/bin/FileCheck /build/buildbot/premerge-monolithic-linux/llvm-project/mlir/test/Target/LLVMIR/llvmir-intrinsics.mlir
# .---command stderr------------
# | /build/buildbot/premerge-monolithic-linux/llvm-project/mlir/test/Target/LLVMIR/llvmir-intrinsics.mlir:1072:15: error: CHECK-DAG: expected string not found in input
# | // CHECK-DAG: declare void @llvm.memcpy.inline.p0.p0.i32(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i32 immarg, i1 immarg)
# |               ^
# | <stdin>:574:143: note: scanning from here
# |  %8 = call <4 x half> @llvm.experimental.constrained.fptrunc.v4f16.v4f32(<4 x float> %1, metadata !"round.upward", metadata !"fpexcept.strict") #20
# |                                                                                                                                               ^
# | 
# | Input file: <stdin>
# | Check file: /build/buildbot/premerge-monolithic-linux/llvm-project/mlir/test/Target/LLVMIR/llvmir-intrinsics.mlir
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |           .
# |           .
# |           .
# |         569:  %3 = call float @llvm.experimental.constrained.fptrunc.f32.f64(double %0, metadata !"round.towardzero", metadata !"fpexcept.ignore") #20 
# |         570:  %4 = call float @llvm.experimental.constrained.fptrunc.f32.f64(double %0, metadata !"round.tonearest", metadata !"fpexcept.maytrap") #20 
# |         571:  %5 = call float @llvm.experimental.constrained.fptrunc.f32.f64(double %0, metadata !"round.upward", metadata !"fpexcept.strict") #20 
# |         572:  %6 = call float @llvm.experimental.constrained.fptrunc.f32.f64(double %0, metadata !"round.downward", metadata !"fpexcept.ignore") #20 
# |         573:  %7 = call float @llvm.experimental.constrained.fptrunc.f32.f64(double %0, metadata !"round.tonearestaway", metadata !"fpexcept.ignore") #20 
# |         574:  %8 = call <4 x half> @llvm.experimental.constrained.fptrunc.v4f16.v4f32(<4 x float> %1, metadata !"round.upward", metadata !"fpexcept.strict") #20 
# | dag:1072                                                                                                                                                   X~~~~~ error: no match found
# |         575:  ret void 
# | dag:1072     ~~~~~~~~~~
# |         576: } 
# | dag:1072     ~~
# |         577:  
# | dag:1072     ~
# |         578: ; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none) 
# | dag:1072     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |         579: declare float @llvm.fmuladd.f32(float, float, float) #0 
# | dag:1072     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |           .
# |           .
# |           .
# | >>>>>>
# `-----------------------------
...

```

https://github.com/llvm/llvm-project/pull/98281