[PATCH] D109441: [FuncSpec] Don't specialise call sites that have the MinSize attribute set

[Sjoerd Meijer via Phabricator via llvm-commits]

SjoerdMeijer created this revision.
SjoerdMeijer added reviewers: ChuanqiXu, snehasish, jaykang10.
Herald added subscribers: ormris, hiraditya.
SjoerdMeijer requested review of this revision.
Herald added a project: LLVM.

Not only the function declaration can have the minsize attribute set, but also the call site. I don't think we would like to specialise when a call instruction has minsize set.


https://reviews.llvm.org/D109441

Files:
  llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
  llvm/test/Transforms/FunctionSpecialization/function-specialization-minsize2.ll


Index: llvm/test/Transforms/FunctionSpecialization/function-specialization-minsize2.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/FunctionSpecialization/function-specialization-minsize2.ll
@@ -0,0 +1,41 @@
+; RUN: opt -function-specialization -func-specialization-size-threshold=3 -S < %s | FileCheck %s
+
+; CHECK-NOT: @compute.1
+; CHECK-NOT: @compute.2
+
+define i64 @main(i64 %x, i1 %flag) {
+entry:
+  br i1 %flag, label %plus, label %minus
+
+plus:
+  %tmp0 = call i64 @compute(i64 %x, i64 (i64)* @plus) #0
+  br label %merge
+
+minus:
+  %tmp1 = call i64 @compute(i64 %x, i64 (i64)* @minus) #0
+  br label %merge
+
+merge:
+  %tmp2 = phi i64 [ %tmp0, %plus ], [ %tmp1, %minus]
+  ret i64 %tmp2
+}
+
+define internal i64 @compute(i64 %x, i64 (i64)* %binop) {
+entry:
+  %tmp0 = call i64 %binop(i64 %x)
+  ret i64 %tmp0
+}
+
+define internal i64 @plus(i64 %x) {
+entry:
+  %tmp0 = add i64 %x, 1
+  ret i64 %tmp0
+}
+
+define internal i64 @minus(i64 %x) {
+entry:
+  %tmp0 = sub i64 %x, 1
+  ret i64 %tmp0
+}
+
+attributes #0 = { minsize optsize }
Index: llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
===================================================================
--- llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
+++ llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
@@ -656,6 +656,8 @@
       if (!isa<CallInst>(U) && !isa<InvokeInst>(U))
         continue;
       auto &CS = *cast<CallBase>(U);
+      if (CS.hasFnAttr(Attribute::MinSize))
+        continue;
 
       // If the parent of the call site will never be executed, we don't need
       // to worry about the passed value.
@@ -664,11 +666,9 @@
 
       auto *V = CS.getArgOperand(A->getArgNo());
       // TrackValueOfGlobalVariable only tracks scalar global variables.
-      if (auto *GV = dyn_cast<GlobalVariable>(V)) {
-        if (!GV->getValueType()->isSingleValueType()) {
+      if (auto *GV = dyn_cast<GlobalVariable>(V))
+        if (!GV->getValueType()->isSingleValueType())
           return false;
-        }
-      }
 
       if (isa<Constant>(V) && (Solver.getLatticeValueFor(V).isConstant() ||
                                EnableSpecializationForLiteralConstant))


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