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llvm-project/llvm/test/Transforms/LowerExpectIntrinsic/phi_merge.ll
Paul Kirth 294f3ce5dd
Reapply "[llvm][IR] Extend BranchWeightMetadata to track provenance o… (#95281) 
…f weights" #95136

Reverts #95060, and relands #86609, with the unintended code generation
changes addressed.

This patch implements the changes to LLVM IR discussed in
https://discourse.llvm.org/t/rfc-update-branch-weights-metadata-to-allow-tracking-branch-weight-origins/75032

In this patch, we add an optional field to MD_prof meatdata nodes for
branch weights, which can be used to distinguish weights added from
llvm.expect* intrinsics from those added via other methods, e.g. from
profiles or inserted by the compiler.

One of the major motivations, is for use with MisExpect diagnostics,
which need to know if branch_weight metadata originates from an
llvm.expect intrinsic. Without that information, we end up checking
branch weights multiple times in the case if ThinLTO + SampleProfiling,
leading to some inaccuracy in how we report MisExpect related
diagnostics to users.

Since we change the format of MD_prof metadata in a fundamental way, we
need to update code handling branch weights in a number of places.

We also update the lang ref for branch weights to reflect the change.
2024-06-12 12:52:28 -07:00

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; RUN: opt -passes=lower-expect -S -o - < %s | FileCheck %s
; RUN: opt -S -passes='function(lower-expect)' < %s | FileCheck %s
; The C case
; if (__builtin_expect((x > goo() && y > hoo() && z > too()), 1))
; For the above case, all 3 branches should be annotated.
;
; if (__builtin_expect((x > goo() && y > hoo() && z > too()), 0))
; For the above case, we don't have enough information, so
; only the last branch is annotated.
define void @foo(i32 %arg, i32 %arg1, i32 %arg2, i32 %arg3) {
; CHECK-LABEL: void @foo
bb:
%tmp8 = call i32 @goo()
%tmp9 = icmp sgt i32 %tmp8, %arg
br i1 %tmp9, label %bb10, label %bb18
; CHECK: !prof [[WEIGHT:![0-9]+]]
bb10: ; preds = %bb
%tmp12 = call i32 @hoo()
%tmp13 = icmp sgt i32 %arg1, %tmp12
br i1 %tmp13, label %bb14, label %bb18
; CHECK: br i1 %tmp13, {{.*}}!prof [[WEIGHT]]
bb14: ; preds = %bb10
%tmp16 = call i32 @too()
%tmp17 = icmp sgt i32 %arg2, %tmp16
br label %bb18
bb18: ; preds = %bb14, %bb10, %bb
%tmp19 = phi i1 [ false, %bb10 ], [ false, %bb ], [ %tmp17, %bb14 ]
%tmp20 = xor i1 %tmp19, true
%tmp21 = xor i1 %tmp20, true
%tmp22 = zext i1 %tmp21 to i32
%tmp23 = sext i32 %tmp22 to i64
%tmp24 = call i64 @llvm.expect.i64(i64 %tmp23, i64 1)
%tmp25 = icmp ne i64 %tmp24, 0
br i1 %tmp25, label %bb26, label %bb28
; CHECK: br i1 %tmp25,{{.*}}!prof [[WEIGHT]]
bb26: ; preds = %bb18
%tmp27 = call i32 @goo()
br label %bb30
bb28: ; preds = %bb18
%tmp29 = call i32 @hoo()
br label %bb30
bb30: ; preds = %bb28, %bb26
ret void
}
define void @foo2(i32 %arg, i32 %arg1, i32 %arg2, i32 %arg3) {
; CHECK-LABEL: void @foo2
bb:
%tmp8 = call i32 @goo()
%tmp9 = icmp sgt i32 %tmp8, %arg
br i1 %tmp9, label %bb10, label %bb18
; CHECK: br i1 %tmp9
; CHECK-NOT: !prof
bb10: ; preds = %bb
%tmp12 = call i32 @hoo()
%tmp13 = icmp sgt i32 %arg1, %tmp12
br i1 %tmp13, label %bb14, label %bb18
; CHECK: br i1 %tmp13
; CHECK-NOT: !prof
bb14: ; preds = %bb10
%tmp16 = call i32 @too()
%tmp17 = icmp sgt i32 %arg2, %tmp16
br label %bb18
bb18: ; preds = %bb14, %bb10, %bb
%tmp19 = phi i1 [ false, %bb10 ], [ false, %bb ], [ %tmp17, %bb14 ]
%tmp20 = xor i1 %tmp19, true
%tmp21 = xor i1 %tmp20, true
%tmp22 = zext i1 %tmp21 to i32
%tmp23 = sext i32 %tmp22 to i64
%tmp24 = call i64 @llvm.expect.i64(i64 %tmp23, i64 0)
%tmp25 = icmp ne i64 %tmp24, 0
br i1 %tmp25, label %bb26, label %bb28
; CHECK: br i1 %tmp25,{{.*}}!prof [[WEIGHT2:![0-9]+]]
bb26: ; preds = %bb18
%tmp27 = call i32 @goo()
br label %bb30
bb28: ; preds = %bb18
%tmp29 = call i32 @hoo()
br label %bb30
bb30: ; preds = %bb28, %bb26
ret void
}
define void @foo_i32(i32 %arg, i32 %arg1, i32 %arg2, i32 %arg3) {
; CHECK-LABEL: void @foo_i32
bb:
%tmp8 = call i32 @goo()
%tmp9 = icmp sgt i32 %tmp8, %arg
br i1 %tmp9, label %bb10, label %bb18
; CHECK: !prof [[WEIGHT]]
bb10: ; preds = %bb
%tmp12 = call i32 @hoo()
%tmp13 = icmp sgt i32 %arg1, %tmp12
br i1 %tmp13, label %bb14, label %bb18
; CHECK: br i1 %tmp13, {{.*}}!prof [[WEIGHT]]
bb14: ; preds = %bb10
%tmp16 = call i32 @too()
%tmp17 = icmp sgt i32 %arg2, %tmp16
br label %bb18
bb18: ; preds = %bb14, %bb10, %bb
%tmp19 = phi i32 [ 5, %bb10 ], [ 5, %bb ], [ %tmp16, %bb14 ]
%tmp23 = sext i32 %tmp19 to i64
%tmp24 = call i64 @llvm.expect.i64(i64 %tmp23, i64 4)
%tmp25 = icmp ne i64 %tmp24, 0
br i1 %tmp25, label %bb26, label %bb28
; CHECK: br i1 %tmp25,{{.*}}!prof [[WEIGHT]]
bb26: ; preds = %bb18
%tmp27 = call i32 @goo()
br label %bb30
bb28: ; preds = %bb18
%tmp29 = call i32 @hoo()
br label %bb30
bb30: ; preds = %bb28, %bb26
ret void
}
define void @foo_i32_not_unlikely(i32 %arg, i32 %arg1, i32 %arg2, i32 %arg3) {
; CHECK-LABEL: void @foo_i32_not_unlikely
bb:
%tmp8 = call i32 @goo()
%tmp9 = icmp sgt i32 %tmp8, %arg
br i1 %tmp9, label %bb10, label %bb18
; CHECK: br i1 %tmp9
; CHECK-NOT: !prof
bb10: ; preds = %bb
%tmp12 = call i32 @hoo()
%tmp13 = icmp sgt i32 %arg1, %tmp12
br i1 %tmp13, label %bb14, label %bb18
; CHECK: br i1 %tmp13
; CHECK-NOT: !prof
bb14: ; preds = %bb10
%tmp16 = call i32 @too()
%tmp17 = icmp sgt i32 %arg2, %tmp16
br label %bb18
bb18: ; preds = %bb14, %bb10, %bb
%tmp19 = phi i32 [ 4, %bb10 ], [ 4, %bb ], [ %tmp16, %bb14 ]
%tmp23 = sext i32 %tmp19 to i64
%tmp24 = call i64 @llvm.expect.i64(i64 %tmp23, i64 4)
%tmp25 = icmp ne i64 %tmp24, 0
br i1 %tmp25, label %bb26, label %bb28
; CHECK: br i1 %tmp25,{{.*}}!prof [[WEIGHT]]
bb26: ; preds = %bb18
%tmp27 = call i32 @goo()
br label %bb30
bb28: ; preds = %bb18
%tmp29 = call i32 @hoo()
br label %bb30
bb30: ; preds = %bb28, %bb26
ret void
}
define void @foo_i32_xor(i32 %arg, i32 %arg1, i32 %arg2, i32 %arg3) {
; CHECK-LABEL: void @foo_i32_xor
bb:
%tmp8 = call i32 @goo()
%tmp9 = icmp sgt i32 %tmp8, %arg
br i1 %tmp9, label %bb10, label %bb18
; CHECK: br i1 %tmp9,{{.*}}!prof [[WEIGHT]]
bb10: ; preds = %bb
%tmp12 = call i32 @hoo()
%tmp13 = icmp sgt i32 %arg1, %tmp12
br i1 %tmp13, label %bb14, label %bb18
; CHECK: br i1 %tmp13,{{.*}}!prof [[WEIGHT]]
bb14: ; preds = %bb10
%tmp16 = call i32 @too()
%tmp17 = icmp sgt i32 %arg2, %tmp16
br label %bb18
bb18: ; preds = %bb14, %bb10, %bb
%tmp19 = phi i32 [ 6, %bb10 ], [ 6, %bb ], [ %tmp16, %bb14 ]
%tmp20 = xor i32 %tmp19, 3
%tmp23 = sext i32 %tmp20 to i64
%tmp24 = call i64 @llvm.expect.i64(i64 %tmp23, i64 4)
%tmp25 = icmp ne i64 %tmp24, 0
br i1 %tmp25, label %bb26, label %bb28
; CHECK: br i1 %tmp25,{{.*}}!prof [[WEIGHT]]
bb26: ; preds = %bb18
%tmp27 = call i32 @goo()
br label %bb30
bb28: ; preds = %bb18
%tmp29 = call i32 @hoo()
br label %bb30
bb30: ; preds = %bb28, %bb26
ret void
}
define void @foo_i8_sext(i32 %arg, i32 %arg1, i8 %arg2, i32 %arg3) {
; CHECK-LABEL: void @foo_i8_sext
bb:
%tmp8 = call i32 @goo()
%tmp9 = icmp sgt i32 %tmp8, %arg
br i1 %tmp9, label %bb10, label %bb18
; CHECK: br i1 %tmp9,{{.*}}!prof [[WEIGHT]]
bb10: ; preds = %bb
%tmp12 = call i32 @hoo()
%tmp13 = icmp sgt i32 %arg1, %tmp12
br i1 %tmp13, label %bb14, label %bb18
; CHECK: br i1 %tmp13,{{.*}}!prof [[WEIGHT]]
bb14: ; preds = %bb10
%tmp16 = call i8 @too8()
%tmp17 = icmp sgt i8 %arg2, %tmp16
br label %bb18
bb18: ; preds = %bb14, %bb10, %bb
%tmp19 = phi i8 [ 255, %bb10 ], [ 255, %bb ], [ %tmp16, %bb14 ]
%tmp23 = sext i8 %tmp19 to i64
; after sign extension, the operand value becomes -1 which does not match 255
%tmp24 = call i64 @llvm.expect.i64(i64 %tmp23, i64 255)
%tmp25 = icmp ne i64 %tmp24, 0
br i1 %tmp25, label %bb26, label %bb28
; CHECK: br i1 %tmp25,{{.*}}!prof [[WEIGHT]]
bb26: ; preds = %bb18
%tmp27 = call i32 @goo()
br label %bb30
bb28: ; preds = %bb18
%tmp29 = call i32 @hoo()
br label %bb30
bb30: ; preds = %bb28, %bb26
ret void
}
define void @foo_i8_sext_not_unlikely(i32 %arg, i32 %arg1, i8 %arg2, i32 %arg3) {
; CHECK-LABEL: void @foo_i8_sext_not_unlikely
bb:
%tmp8 = call i32 @goo()
%tmp9 = icmp sgt i32 %tmp8, %arg
br i1 %tmp9, label %bb10, label %bb18
; CHECK: br i1 %tmp9
; CHECK-NOT: !prof
bb10: ; preds = %bb
%tmp12 = call i32 @hoo()
%tmp13 = icmp sgt i32 %arg1, %tmp12
br i1 %tmp13, label %bb14, label %bb18
; CHECK: br i1 %tmp13
; CHECK-NOT: !prof
bb14: ; preds = %bb10
%tmp16 = call i8 @too8()
%tmp17 = icmp sgt i8 %arg2, %tmp16
br label %bb18
bb18: ; preds = %bb14, %bb10, %bb
%tmp19 = phi i8 [ 255, %bb10 ], [ 255, %bb ], [ %tmp16, %bb14 ]
%tmp23 = sext i8 %tmp19 to i64
; after sign extension, the operand value becomes -1 which matches -1
%tmp24 = call i64 @llvm.expect.i64(i64 %tmp23, i64 -1)
%tmp25 = icmp ne i64 %tmp24, 0
br i1 %tmp25, label %bb26, label %bb28
; CHECK: br i1 %tmp25,{{.*}}!prof [[WEIGHT]]
bb26: ; preds = %bb18
%tmp27 = call i32 @goo()
br label %bb30
bb28: ; preds = %bb18
%tmp29 = call i32 @hoo()
br label %bb30
bb30: ; preds = %bb28, %bb26
ret void
}
define void @foo_i32_xor_not_unlikely(i32 %arg, i32 %arg1, i32 %arg2, i32 %arg3) {
; CHECK-LABEL: void @foo_i32_xor_not_unlikely
bb:
%tmp8 = call i32 @goo()
%tmp9 = icmp sgt i32 %tmp8, %arg
br i1 %tmp9, label %bb10, label %bb18
; CHECK: br i1 %tmp9
; CHECK-NOT: !prof
bb10: ; preds = %bb
%tmp12 = call i32 @hoo()
%tmp13 = icmp sgt i32 %arg1, %tmp12
br i1 %tmp13, label %bb14, label %bb18
; CHECK: br i1 %tmp13
; CHECK-NOT: !prof
bb14: ; preds = %bb10
%tmp16 = call i32 @too()
%tmp17 = icmp sgt i32 %arg2, %tmp16
br label %bb18
bb18: ; preds = %bb14, %bb10, %bb
%tmp19 = phi i32 [ 6, %bb10 ], [ 6, %bb ], [ %tmp16, %bb14 ]
%tmp20 = xor i32 %tmp19, 2
%tmp23 = sext i32 %tmp20 to i64
%tmp24 = call i64 @llvm.expect.i64(i64 %tmp23, i64 4)
%tmp25 = icmp ne i64 %tmp24, 0
br i1 %tmp25, label %bb26, label %bb28
; CHECK: br i1 %tmp25,{{.*}}!prof [[WEIGHT]]
bb26: ; preds = %bb18
%tmp27 = call i32 @goo()
br label %bb30
bb28: ; preds = %bb18
%tmp29 = call i32 @hoo()
br label %bb30
bb30: ; preds = %bb28, %bb26
ret void
}
declare i32 @goo()
declare i32 @hoo()
declare i32 @too()
declare i8 @too8()
; Function Attrs: nounwind readnone
declare i64 @llvm.expect.i64(i64, i64)
!llvm.ident = !{!0}
!0 = !{!"clang version 5.0.0 (trunk 302965)"}
; CHECK: [[WEIGHT]] = !{!"branch_weights", !"expected", i32 2000, i32 1}
; CHECK: [[WEIGHT2]] = !{!"branch_weights", !"expected", i32 1, i32 2000}
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