[llvm-branch-commits] [llvm] 19ab181 - [llvm-reduce] Fix removal of unused llvm intrinsics declarations

[Roman Lebedev via llvm-branch-commits]

Author: Roman Lebedev
Date: 2021-01-03T01:45:47+03:00
New Revision: 19ab1817b61d3b716f69f78f727de8bd8887f53f

URL: https://github.com/llvm/llvm-project/commit/19ab1817b61d3b716f69f78f727de8bd8887f53f
DIFF: https://github.com/llvm/llvm-project/commit/19ab1817b61d3b716f69f78f727de8bd8887f53f.diff

LOG: [llvm-reduce] Fix removal of unused llvm intrinsics declarations

ee6e25e4391a6d3ac0a3c89615474e512f44cda6 changed
the delta pass to skip intrinsics, which means we may end up being
left with declarations of intrinsics, that aren't otherwise referenced
in the module. This is obviously unwanted, do drop them.

Added: 
    llvm/test/Reduce/remove-unused-declarations.ll

Modified: 
    llvm/tools/llvm-reduce/deltas/ReduceFunctions.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/test/Reduce/remove-unused-declarations.ll b/llvm/test/Reduce/remove-unused-declarations.ll
new file mode 100644
index 000000000000..5ae3a3edbad0
--- /dev/null
+++ b/llvm/test/Reduce/remove-unused-declarations.ll
@@ -0,0 +1,21 @@
+; RUN: llvm-reduce --test FileCheck --test-arg --check-prefixes=CHECK-ALL,CHECK-INTERESTINGNESS --test-arg %s --test-arg --input-file %s -o %t
+; RUN: cat %t | FileCheck --check-prefixes=CHECK-ALL,CHECK-FINAL --implicit-check-not=uninteresting %s
+
+declare void @llvm.uninteresting()
+declare void @uninteresting()
+
+; CHECK-ALL: declare void @llvm.interesting()
+; CHECK-ALL: declare void @interesting()
+declare void @llvm.interesting()
+declare void @interesting()
+
+; CHECK-ALL: define void @main() {
+; CHECK-ALL-NEXT:  call void @llvm.interesting()
+; CHECK-ALL-NEXT:   call void @interesting()
+; CHECK-ALL-NEXT:   ret void
+; CHECK-ALL-NEXT: }
+define void @main() {
+  call void @llvm.interesting()
+  call void @interesting()
+  ret void
+}

diff  --git a/llvm/tools/llvm-reduce/deltas/ReduceFunctions.cpp b/llvm/tools/llvm-reduce/deltas/ReduceFunctions.cpp
index 6bb8f81c3dbd..d100935ee422 100644
--- a/llvm/tools/llvm-reduce/deltas/ReduceFunctions.cpp
+++ b/llvm/tools/llvm-reduce/deltas/ReduceFunctions.cpp
@@ -33,8 +33,8 @@ static void extractFunctionsFromModule(const std::vector<Chunk> &ChunksToKeep,
           [&O](Function &F) {
             // Intrinsics don't have function bodies that are useful to
             // reduce. Additionally, intrinsics may have additional operand
-            // constraints.
-            return !F.isIntrinsic() && !O.shouldKeep();
+            // constraints. But, do drop intrinsics that are not referenced.
+            return (!F.isIntrinsic() || F.use_empty()) && !O.shouldKeep();
           });
 
   // Then, drop body of each of them. We want to batch this and do nothing else
@@ -51,7 +51,7 @@ static void extractFunctionsFromModule(const std::vector<Chunk> &ChunksToKeep,
   }
 }
 
-/// Counts the amount of non-declaration functions and prints their
+/// Counts the amount of functions and prints their
 /// respective name & index
 static int countFunctions(Module *Program) {
   // TODO: Silence index with --quiet flag
@@ -59,7 +59,7 @@ static int countFunctions(Module *Program) {
   errs() << "Function Index Reference:\n";
   int FunctionCount = 0;
   for (auto &F : *Program) {
-    if (F.isIntrinsic())
+    if (F.isIntrinsic() && !F.use_empty())
       continue;
 
     errs() << '\t' << ++FunctionCount << ": " << F.getName() << '\n';