[PATCH] D157615: [ExtendLifetimes][1/4] Add "disable-post-ra" function attribute to disable the post-regalloc scheduler

[Orlando Cazalet-Hyams via Phabricator via llvm-commits]

Orlando added inline comments.


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Comment at: llvm/lib/CodeGen/PostRASchedulerList.cpp:282
 
+  if (Fn.getFunction().hasFnAttribute("disable-post-ra"))
+    return false;
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bikeshed: `disable-post-ra` seems potentially unclear. Perhaps `disable-post-ra-sched`?


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Comment at: llvm/test/CodeGen/X86/suppress-post-ra.ll:7
+; RUN: llc < %s -O2 -print-after=post-RA-sched 2>&1 > /dev/null - | tail -n +2 > %t2
+; RUN: diff %t1 %t2
+;
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Do you need to run all the `O2` passes? Can we not just use `--run-pass=post-RA-sched`?

Secondly, IMO it'd be good to check that post-RA-sched does something to the input when the attribute isn't present to avoid a rotten green test. You could probably achieve that with a `sed` command to add/remove the attribute (see example in [dbg-empty-metadata-lowering.ll](https://github.com/llvm/llvm-project/blob/main/llvm/test/DebugInfo/X86/dbg-empty-metadata-lowering.ll)).


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Comment at: llvm/test/CodeGen/X86/suppress-post-ra.ll:21
+  %0 = bitcast i32* %val to i8*
+  call void @llvm.lifetime.start(i64 4, i8* %0) #3
+  %1 = load i32, i32* @data, align 4, !tbaa !2
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Can the tbaa metadata and lifetime markers be removed?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D157615/new/

https://reviews.llvm.org/D157615