[CallSite Removal] a CallBase is never an IndirectCall for isInlineAsm
authorNick Desaulniers <ndesaulniers@google.com>
Mon, 6 Apr 2020 23:14:40 +0000 (16:14 -0700)
committerNick Desaulniers <ndesaulniers@google.com>
Mon, 6 Apr 2020 23:14:46 +0000 (16:14 -0700)
Summary:
Thanks to Bill Wendling (void) for the report and steps to reproduce.  It looks
like this was missed during r350508's cleanup of the CallSite split into
CallBase, CallInst, and CallBrInst.

This was exposed by running pgo on a callbr, which was creating a ptrtoint to
the inline asm thinking it was an indirect call. The relevant callchain looks
like:

    IndirectCallPromotionPlugin::run()
    -> PGOIndirectCallVisitor::findIndirectCalls()
      -> PGOIndirectCallVisitor::visitCallBase()
        -> CallBase::isIndirectCall()

Reviewers: void, chandlerc

Reviewed By: void

Subscribers: hiraditya, llvm-commits, craig.topper, srhines

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77600

llvm/lib/IR/Instructions.cpp
llvm/test/Transforms/PGOProfile/callbr.ll [new file with mode: 0644]

index 37e194a..3e1639b 100644 (file)
@@ -267,10 +267,7 @@ bool CallBase::isIndirectCall() const {
   const Value *V = getCalledValue();
   if (isa<Function>(V) || isa<Constant>(V))
     return false;
-  if (const CallInst *CI = dyn_cast<CallInst>(this))
-    if (CI->isInlineAsm())
-      return false;
-  return true;
+  return !isInlineAsm();
 }
 
 /// Tests if this call site must be tail call optimized. Only a CallInst can
diff --git a/llvm/test/Transforms/PGOProfile/callbr.ll b/llvm/test/Transforms/PGOProfile/callbr.ll
new file mode 100644 (file)
index 0000000..626b774
--- /dev/null
@@ -0,0 +1,17 @@
+; RUN: opt -pgo-instr-gen -S 2>&1 < %s | FileCheck %s
+
+define i32 @a() {
+entry:
+; CHECK-NOT: ptrtoint void (i8*)* asm sideeffect
+; CHECK: callbr void asm sideeffect
+  %retval = alloca i32, align 4
+  callbr void asm sideeffect "", "X,~{dirflag},~{fpsr},~{flags}"(i8* blockaddress(@a, %b)) #1
+          to label %asm.fallthrough [label %b]
+
+asm.fallthrough:
+  br label %b
+
+b:
+  %0 = load i32, i32* %retval, align 4
+  ret i32 %0
+}