Now that #149310 has restricted lifetime intrinsics to only work on
allocas, we can also drop the explicit size argument. Instead, the size
is implied by the alloca.
This removes the ability to only mark a prefix of an alloca alive/dead.
We never used that capability, so we should remove the need to handle
that possibility everywhere (though many key places, including stack
coloring, did not actually respect this).
Previously the inliner always produced a memcpy with alignment 1 for src
and destination, leading to potentially suboptimal Codegen.
Since the Src ptr alignment is only available through the CallBase it
has to be passed to HandleByValArgumentInit. Dst Alignment is already
known so it doesn't have to be passed along.
If there is no specified Src Alignment my changes cause the ptr to have
no align data attached instead of align 1 as before (see
inline-tail.ll), I believe this is fine but since I'm a first time
contributor, please confirm.
My changes are already covered by 4 existing regression tests, so I did
not add any additional ones.
The example from #45778 now results in:
```C
opt -S -passes=inline,instcombine,sroa,instcombine test.ll
define dso_local i32 @test(ptr %t) {
entry:
%.sroa.0.0.copyload = load ptr, ptr %t, align 8 # this used to be align 1 in the original issue
%arrayidx.i = getelementptr inbounds nuw i8, ptr %.sroa.0.0.copyload, i64 24
%0 = load i32, ptr %arrayidx.i, align 4
ret i32 %0
}
```
Fixes#45778.
Original commit: a61f9fe31750cee65c726fb51f1b14e31e177258
Multiple 2-stage buildbots were reporting failures. These issues have been
addressed separately.
Fixes: https://github.com/llvm/llvm-project/issues/87534.
A logic issue arose when inlining via `CloneAndPruneFunctionInto`,
which, besides cloning, performs instruction simplification as well.
By the time a new cloned instruction is being simplified, phi-nodes
are not remapped yet as the whole CFG needs to be processed first.
As `VMap` state at this stage is incomplete, `threadCmpOverPHI` and
variants could lead to unsound optimizations. This issue has been
addressed by performing basic constant folding while cloning, and
postponing instruction simplification once phi-nodes are revisited.
Fixes: https://github.com/llvm/llvm-project/issues/87534.
