2 Commits

Author SHA1 Message Date
Simon Pilgrim
d391e4fe84 [X86] Update RET/LRET instruction to use the same naming convention as IRET (PR36876). NFC
Be more consistent in the naming convention for the various RET instructions to specify in terms of bitwidth.

Helps prevent future scheduler model mismatches like those that were only addressed in D44687.

Differential Revision: https://reviews.llvm.org/D113302
2021-11-07 15:06:54 +00:00
Hongtao Yu
d0e42037bf [CSSPGO] MIR target-independent pseudo instruction for pseudo-probe intrinsic
This change introduces a MIR target-independent pseudo instruction corresponding to the IR intrinsic llvm.pseudoprobe for pseudo-probe block instrumentation. Please refer to https://reviews.llvm.org/D86193 for the whole story.

An `llvm.pseudoprobe` intrinsic call will be lowered into a target-independent operation named `PSEUDO_PROBE`. Given the following instrumented IR,

```
define internal void @foo2(i32 %x, void (i32)* %f) !dbg !4 {
bb0:
   %cmp = icmp eq i32 %x, 0
   call void @llvm.pseudoprobe(i64 837061429793323041, i64 1)
   br i1 %cmp, label %bb1, label %bb2
bb1:
   call void @llvm.pseudoprobe(i64 837061429793323041, i64 2)
   br label %bb3
bb2:
   call void @llvm.pseudoprobe(i64 837061429793323041, i64 3)
   br label %bb3
bb3:
   call void @llvm.pseudoprobe(i64 837061429793323041, i64 4)
   ret void
}
```
the corresponding MIR is shown below. Note that block `bb3` is duplicated into `bb1` and `bb2` where its probe is duplicated too. This allows for an accurate execution count to be collected for `bb3`, which is basically the sum of the counts of `bb1` and `bb2`.

```
bb.0.bb0:
   frame-setup PUSH64r undef $rax, implicit-def $rsp, implicit $rsp
   TEST32rr killed renamable $edi, renamable $edi, implicit-def $eflags
   PSEUDO_PROBE 837061429793323041, 1, 0
   $edi = MOV32ri 1, debug-location !13; test.c:0
   JCC_1 %bb.1, 4, implicit $eflags

bb.2.bb2:
   PSEUDO_PROBE 837061429793323041, 3, 0
   PSEUDO_PROBE 837061429793323041, 4, 0
   $rax = frame-destroy POP64r implicit-def $rsp, implicit $rsp
   RETQ

bb.1.bb1:
   PSEUDO_PROBE 837061429793323041, 2, 0
   PSEUDO_PROBE 837061429793323041, 4, 0
   $rax = frame-destroy POP64r implicit-def $rsp, implicit $rsp
   RETQ
```

The target op PSEUDO_PROBE will be converted into a piece of binary data by the object emitter with no machine instructions generated. This is done in a different patch.

Reviewed By: wmi

Differential Revision: https://reviews.llvm.org/D86495
2020-11-20 10:52:43 -08:00