[llvm] r313686 - Revert "[MIRPrinter] Print empty successor lists when they cannot be guessed"

[Quentin Colombet via llvm-commits]

Author: qcolombet
Date: Tue Sep 19 15:03:50 2017
New Revision: 313686

URL: http://llvm.org/viewvc/llvm-project?rev=313686&view=rev
Log:
Revert "[MIRPrinter] Print empty successor lists when they cannot be guessed"

This reverts commit r313685.

I thought I had ran ninja check, but apparently I didn't...
Need to update a bunch of mir tests.

Removed:
    llvm/trunk/test/CodeGen/MIR/X86/unreachable_block.ll
Modified:
    llvm/trunk/lib/CodeGen/MIRPrinter.cpp

Modified: llvm/trunk/lib/CodeGen/MIRPrinter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MIRPrinter.cpp?rev=313686&r1=313685&r2=313686&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MIRPrinter.cpp (original)
+++ llvm/trunk/lib/CodeGen/MIRPrinter.cpp Tue Sep 19 15:03:50 2017
@@ -598,7 +598,8 @@ void MIPrinter::print(const MachineBasic
   bool HasLineAttributes = false;
   // Print the successors
   bool canPredictProbs = canPredictBranchProbabilities(MBB);
-  if (!SimplifyMIR || !canPredictProbs || !canPredictSuccessors(MBB)) {
+  if (!MBB.succ_empty() && (!SimplifyMIR || !canPredictProbs ||
+                            !canPredictSuccessors(MBB))) {
     OS.indent(2) << "successors: ";
     for (auto I = MBB.succ_begin(), E = MBB.succ_end(); I != E; ++I) {
       if (I != MBB.succ_begin())

Removed: llvm/trunk/test/CodeGen/MIR/X86/unreachable_block.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/MIR/X86/unreachable_block.ll?rev=313685&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/MIR/X86/unreachable_block.ll (original)
+++ llvm/trunk/test/CodeGen/MIR/X86/unreachable_block.ll (removed)
@@ -1,48 +0,0 @@
-; RUN: llc -mtriple x86_64-- -stop-before peephole-opt -o %t.mir %s
-; RUN: llc -mtriple x86_64-- -run-pass none %t.mir -verify-machineinstrs -o - | FileCheck %s
-
-; Unreachable blocks in the machine instr representation are these
-; weird empty blocks with no successors.
-; The MIR printer used to not print empty lists of successors. However,
-; the MIR parser now treats non-printed list of successors as "please
-; guess it for me". As a result, the parser tries to guess the list of
-; successors and given the block is empty, just assumes it falls through
-; the next block.
-;
-; The following test case used to fail the verifier because the false
-; path ended up falling through split.true and now, the definition of
-; %v does not dominate all its uses.
-; Indeed, we go from the following CFG:
-;          entry
-;         /      \
-;    true (def)   false
-;        |
-;  split.true (use)
-;
-; To this one:
-;          entry
-;         /      \
-;    true (def)   false
-;        |        /  <-- invalid edge
-;  split.true (use)
-;
-; Because of the invalid edge, we get the "def does not
-; dominate all uses" error.
-;
-; CHECK-LABEL: name: foo
-; CHECK-LABEL: bb.{{[0-9]+}}.false:
-; CHECK-NEXT: successors:
-; CHECK-NOT: %bb.{{[0-9]+}}.split.true
-; CHECK-LABEL: bb.{{[0-9]+}}.split.true:
-define void @foo(i32* %bar) {
-  br i1 undef, label %true, label %false
-true:
-  %v = load i32, i32* %bar
-  br label %split.true
-false:
-  unreachable
-split.true:
-  %vInc = add i32 %v, 1
-  store i32 %vInc, i32* %bar
-  ret void
-}