From: Arnold Schwaighofer <aschwaighofer@apple.com>
Date: Mon, 27 Nov 2017 19:03:40 +0000 (+0000)
Subject: Inliner: Don't mark notail calls with the 'tail' attribute
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=ec3e9648821233f82e2caa02ed023e1b4a30de23;p=llvm

Inliner: Don't mark notail calls with the 'tail' attribute

enum TailCallKind { TCK_None = 0, TCK_Tail = 1, TCK_MustTail = 2,
                    TCK_NoTail = 3 };

TCK_NoTail is greater than TCK_Tail so taking the min does not do the
correct thing.

rdar://35639547

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319075 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Utils/InlineFunction.cpp b/lib/Transforms/Utils/InlineFunction.cpp
index 23a72e86e50..15a8bf22922 100644
--- a/lib/Transforms/Utils/InlineFunction.cpp
+++ b/lib/Transforms/Utils/InlineFunction.cpp
@@ -1850,7 +1850,8 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
         //    f ->          g -> musttail f  ==>  f ->          f
         //    f ->          g ->     tail f  ==>  f ->          f
         CallInst::TailCallKind ChildTCK = CI->getTailCallKind();
-        ChildTCK = std::min(CallSiteTailKind, ChildTCK);
+        if (ChildTCK != CallInst::TCK_NoTail)
+          ChildTCK = std::min(CallSiteTailKind, ChildTCK);
         CI->setTailCallKind(ChildTCK);
         InlinedMustTailCalls |= CI->isMustTailCall();
 
diff --git a/test/Transforms/Inline/inline-tail.ll b/test/Transforms/Inline/inline-tail.ll
index 66a6be7a59b..7b0fe57b68e 100644
--- a/test/Transforms/Inline/inline-tail.ll
+++ b/test/Transforms/Inline/inline-tail.ll
@@ -181,3 +181,18 @@ define i32 @test_mixedret_a(i1 zeroext %b) {
   %rv = musttail call i32 @test_mixedret_b(i1 zeroext %b)
   ret i32 %rv
 }
+
+declare i32 @donttailcall()
+
+define i32 @notail() {
+  %rv = notail call i32 @donttailcall()
+  ret i32 %rv
+}
+
+; CHECK: @test_notail
+; CHECK: notail call i32 @donttailcall
+; CHECK: ret
+define i32 @test_notail() {
+  %rv = tail call i32 @notail()
+  ret i32 %rv
+}