[llvm] [mlir] [IR][PGO] Verify invalid `MD_prof` metadata on instructions (PR #145576)

[Mircea Trofin via llvm-commits]

https://github.com/mtrofin created https://github.com/llvm/llvm-project/pull/145576

[IR][PGO] Verify invalid `MD_prof` metadata on instructions

change

>From 2f7a277026dd130e1d2b0a761b5c0d5853ed8aee Mon Sep 17 00:00:00 2001
From: Mircea Trofin <mtrofin at google.com>
Date: Tue, 24 Jun 2025 11:15:33 -0700
Subject: [PATCH 1/2] [IR][PGO] Verify invalid `MD_prof` metadata on
 instructions


>From 5be0d4be00e22abaa3c20fb4d63c45dcd526d9df Mon Sep 17 00:00:00 2001
From: Mircea Trofin <mtrofin at google.com>
Date: Tue, 24 Jun 2025 11:21:14 -0700
Subject: [PATCH 2/2] change

---
 llvm/lib/IR/Verifier.cpp                      |  3 ++
 .../SimplifyCFG/preserve-branchweights.ll     | 43 +++----------------
 .../Target/LLVMIR/Import/import-failure.ll    | 16 -------
 3 files changed, 8 insertions(+), 54 deletions(-)

diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 71261343b3482..ae95e3e2bff8d 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -5008,6 +5008,9 @@ void Verifier::visitProfMetadata(Instruction &I, MDNode *MD) {
       Check(mdconst::dyn_extract<ConstantInt>(MDO),
             "!prof brunch_weights operand is not a const int");
     }
+  } else {
+    Check(ProfName == "VP", "expected either branch_weights or VP profile name",
+          MD);
   }
 }
 
diff --git a/llvm/test/Transforms/SimplifyCFG/preserve-branchweights.ll b/llvm/test/Transforms/SimplifyCFG/preserve-branchweights.ll
index fb607c72a0e35..5bc0aa07a9e10 100644
--- a/llvm/test/Transforms/SimplifyCFG/preserve-branchweights.ll
+++ b/llvm/test/Transforms/SimplifyCFG/preserve-branchweights.ll
@@ -38,45 +38,12 @@ Z:
   ret void
 }
 
-; Make sure the metadata name string is "branch_weights" before propagating it.
-
-define void @fake_weights(i1 %a, i1 %b) {
-; CHECK-LABEL: @fake_weights(
-; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[A_NOT:%.*]] = xor i1 [[A:%.*]], true
-; CHECK-NEXT:    [[C:%.*]] = or i1 [[B:%.*]], false
-; CHECK-NEXT:    [[OR_COND:%.*]] = select i1 [[A_NOT]], i1 [[C]], i1 false
-; CHECK-NEXT:    br i1 [[OR_COND]], label [[Z:%.*]], label [[Y:%.*]], !prof [[PROF1:![0-9]+]]
-; CHECK:       common.ret:
-; CHECK-NEXT:    ret void
-; CHECK:       Y:
-; CHECK-NEXT:    call void @helper(i32 0)
-; CHECK-NEXT:    br label [[COMMON_RET:%.*]]
-; CHECK:       Z:
-; CHECK-NEXT:    call void @helper(i32 1)
-; CHECK-NEXT:    br label [[COMMON_RET]]
-;
-entry:
-  br i1 %a, label %Y, label %X, !prof !12
-X:
-  %c = or i1 %b, false
-  br i1 %c, label %Z, label %Y, !prof !1
-
-Y:
-  call void @helper(i32 0)
-  ret void
-
-Z:
-  call void @helper(i32 1)
-  ret void
-}
-
 define void @test2(i1 %a, i1 %b) {
 ; CHECK-LABEL: @test2(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[C:%.*]] = or i1 [[B:%.*]], false
 ; CHECK-NEXT:    [[OR_COND:%.*]] = select i1 [[A:%.*]], i1 [[C]], i1 false
-; CHECK-NEXT:    br i1 [[OR_COND]], label [[Z:%.*]], label [[Y:%.*]], !prof [[PROF2:![0-9]+]]
+; CHECK-NEXT:    br i1 [[OR_COND]], label [[Z:%.*]], label [[Y:%.*]], !prof [[PROF1:![0-9]+]]
 ; CHECK:       common.ret:
 ; CHECK-NEXT:    ret void
 ; CHECK:       Y:
@@ -107,7 +74,7 @@ define void @test3(i1 %a, i1 %b) {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[C:%.*]] = or i1 [[B:%.*]], false
 ; CHECK-NEXT:    [[OR_COND:%.*]] = select i1 [[A:%.*]], i1 [[C]], i1 false
-; CHECK-NEXT:    br i1 [[OR_COND]], label [[Z:%.*]], label [[Y:%.*]], !prof [[PROF1]]
+; CHECK-NEXT:    br i1 [[OR_COND]], label [[Z:%.*]], label [[Y:%.*]], !prof [[PROF2:![0-9]+]]
 ; CHECK:       common.ret:
 ; CHECK-NEXT:    ret void
 ; CHECK:       Y:
@@ -138,7 +105,7 @@ define void @test4(i1 %a, i1 %b) {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[C:%.*]] = or i1 [[B:%.*]], false
 ; CHECK-NEXT:    [[OR_COND:%.*]] = select i1 [[A:%.*]], i1 [[C]], i1 false
-; CHECK-NEXT:    br i1 [[OR_COND]], label [[Z:%.*]], label [[Y:%.*]], !prof [[PROF1]]
+; CHECK-NEXT:    br i1 [[OR_COND]], label [[Z:%.*]], label [[Y:%.*]], !prof [[PROF2]]
 ; CHECK:       common.ret:
 ; CHECK-NEXT:    ret void
 ; CHECK:       Y:
@@ -1136,8 +1103,8 @@ exit:
 ; CHECK: attributes #[[ATTR2:[0-9]+]] = { noredzone nounwind ssp memory(none) }
 ;.
 ; CHECK: [[PROF0]] = !{!"branch_weights", i32 5, i32 11}
-; CHECK: [[PROF1]] = !{!"branch_weights", i32 1, i32 3}
-; CHECK: [[PROF2]] = !{!"branch_weights", i32 1, i32 5}
+; CHECK: [[PROF1]] = !{!"branch_weights", i32 1, i32 5}
+; CHECK: [[PROF2]] = !{!"branch_weights", i32 1, i32 3}
 ; CHECK: [[PROF3]] = !{!"branch_weights", i32 7, i32 1, i32 2}
 ; CHECK: [[PROF4]] = !{!"branch_weights", i32 49, i32 12, i32 24, i32 35}
 ; CHECK: [[PROF5]] = !{!"branch_weights", i32 11, i32 5}
diff --git a/mlir/test/Target/LLVMIR/Import/import-failure.ll b/mlir/test/Target/LLVMIR/Import/import-failure.ll
index a05a2b4bd4507..d48be66f2063e 100644
--- a/mlir/test/Target/LLVMIR/Import/import-failure.ll
+++ b/mlir/test/Target/LLVMIR/Import/import-failure.ll
@@ -258,22 +258,6 @@ end:
 
 ; // -----
 
-; CHECK:      <unknown>
-; CHECK-SAME: warning: expected function_entry_count to be attached to a function
-; CHECK:      warning: unhandled metadata: !0 = !{!"function_entry_count", i64 42}
-define void @cond_br(i1 %arg) {
-entry:
-  br i1 %arg, label %bb1, label %bb2, !prof !0
-bb1:
-  ret void
-bb2:
-  ret void
-}
-
-!0 = !{!"function_entry_count", i64 42}
-
-; // -----
-
 ; CHECK:      <unknown>
 ; CHECK-SAME: warning: dropped instruction: call void @llvm.experimental.noalias.scope.decl(metadata !0)
 define void @unused_scope() {