llvm-6502/alloca-size-one.ll at master - llvm-6502 - Applefritter: Git

6502/llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-06-17 03:29:52 +00:00

Duncan P. N. Exon Smith 95ff656ae0 AsmWriter: Write alloca array size explicitly (and -instcombine fixup)

Write the `alloca` array size explicitly when it's non-canonical.
Previously, if the array size was `iX 1` (where X is not 32), the type
would mutate to `i32` when round-tripping through assembly.

The testcase I added fails in `verify-uselistorder` (as well as
`FileCheck`), since the use-lists for `i32 1` and `i64 1` change.
(Manman Ren came across this when running `verify-uselistorder` on some
non-trivial, optimized code as part of PR5680.)

The type mutation started with r104911, which allowed array sizes to be
something other than an `i32`.  Starting with r204945, we
"canonicalized" to `i64` on 64-bit platforms -- and then on every
round-trip through assembly, mutated back to `i32`.

I bundled a fixup for `-instcombine` to avoid r204945 on scalar
allocations.  (There wasn't a clean way to sequence this into two
commits, since the assembly change on its own caused testcase churn, and
the `-instcombine` change can't be tested without the assembly changes.)

An obvious alternative fix -- change `AllocaInst::AllocaInst()`,
`AsmWriter` and `LLParser` to treat `intptr_t` as the canonical type for
scalar allocations -- was rejected out of hand, since this required
teaching them each about the data layout.

A follow-up commit will add an `-instcombine` to canonicalize the scalar
allocation array size to `i32 1` rather than leaving `iX 1` alone.

rdar://problem/20075773

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232200 91177308-0d34-0410-b5e6-96231b3b80d8

2015-03-13 19:30:44 +00:00

12 lines

305 B

LLVM

Raw Permalink Blame History

 ; RUN: llvm-as < %s | llvm-dis | llvm-as | llvm-dis | FileCheck %s
 ; RUN: verify-uselistorder %s
 define void @foo() {
 entry:
 ; CHECK: %alloc32 = alloca i1, align 8
 ; CHECK: %alloc64 = alloca i1, i64 1, align 8
   %alloc32 = alloca i1, i32 1, align 8
   %alloc64 = alloca i1, i64 1, align 8
   unreachable
 }