[PATCH] D104606: llvm-diff: add support for diffing the callbr instruction

[Bill Wendling via Phabricator via llvm-commits]

void created this revision.
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The only wrinkle is that we can't process the "blockaddress" arguments
of the callbr until the blocks have been equated. So we force them to be
"unified" before checking.

This was left out when the callbr instruction was added.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D104606

Files:
  llvm/test/tools/llvm-diff/callbr.ll
  llvm/tools/llvm-diff/DifferenceEngine.cpp


Index: llvm/tools/llvm-diff/DifferenceEngine.cpp
===================================================================
--- llvm/tools/llvm-diff/DifferenceEngine.cpp
+++ llvm/tools/llvm-diff/DifferenceEngine.cpp
@@ -284,6 +284,27 @@
       }
       return false;
 
+    } else if (isa<CallBrInst>(L)) {
+      CallBrInst &LI = cast<CallBrInst>(*L);
+      CallBrInst &RI = cast<CallBrInst>(*R);
+      if (LI.getNumIndirectDests() != RI.getNumIndirectDests()) {
+        if (Complain)
+          Engine.log("callbr # of indirect destinations differ");
+        return true;
+      }
+
+      // Perform the "try unify" step so that we can equate the indirect
+      // destinations before checking the call site.
+      for (unsigned i = 0; i < LI.getNumIndirectDests(); i++)
+        tryUnify(LI.getIndirectDest(i), RI.getIndirectDest(i));
+
+      if (diffCallSites(LI, RI, Complain))
+        return true;
+
+      if (TryUnify)
+        tryUnify(LI.getDefaultDest(), RI.getDefaultDest());
+      return false;
+
     } else if (isa<BranchInst>(L)) {
       BranchInst *LI = cast<BranchInst>(L);
       BranchInst *RI = cast<BranchInst>(R);
Index: llvm/test/tools/llvm-diff/callbr.ll
===================================================================
--- /dev/null
+++ llvm/test/tools/llvm-diff/callbr.ll
@@ -0,0 +1,39 @@
+; RUN: not llvm-diff %s %s 2>&1 | FileCheck %s
+
+define void @foo() {
+entry:
+  callbr void asm sideeffect "", "X,X,~{dirflag},~{fpsr},~{flags}"(i8* blockaddress(@foo, %return), i8* blockaddress(@foo, %t_no))
+          to label %asm.fallthrough [label %return, label %t_no]
+
+asm.fallthrough:
+  br label %return
+
+t_no:
+  br label %return
+
+return:
+  ret void
+}
+
+; CHECK:      in function bar:
+; CHECK-NOT:  in function foo:
+; CHECK-NEXT:  in block %entry:
+; CHECK-NEXT:    >   callbr void asm sideeffect "", "X,X,~{dirflag},~{fpsr},~{flags}"(i8* blockaddress(@foo, %t_no), i8* blockaddress(@foo, %return))
+; CHECK-NEXT:          to label %asm.fallthrough [label %return, label %t_no]
+; CHECK-NEXT:    <   callbr void asm sideeffect "", "X,X,~{dirflag},~{fpsr},~{flags}"(i8* blockaddress(@foo, %t_no), i8* blockaddress(@foo, %return))
+; CHECK-NEXT:          to label %asm.fallthrough [label %return, label %t_no]
+
+define void @bar() {
+entry:
+  callbr void asm sideeffect "", "X,X,~{dirflag},~{fpsr},~{flags}"(i8* blockaddress(@foo, %t_no), i8* blockaddress(@foo, %return))
+          to label %asm.fallthrough [label %return, label %t_no]
+
+asm.fallthrough:
+  br label %return
+
+t_no:
+  br label %return
+
+return:
+  ret void
+}


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