[LoopInterchange] Creates invalid IR: PHINode should have one entry for each predecessor of its parent basic block! #149730
Description
See also: https://godbolt.org/z/xaKeMP6zh
This input:
bool a;
short b;
void fn1(bool c, short d[][2][2]) {
for (char e = 0; e < (char)b; e++)
for (char f(c); f < 020; f += 2)
a = d[f][f][f] ?: d[e][f][e] - d[e][f + 2][e];
}
compiled with: -std=c++11 -Ofast -floop-interchange -mcpu=grace
Results in this crash:
#0 0x0000000003c90a38 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3c90a38)
#1 0x0000000003c8e40c llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3c8e40c)
#2 0x0000000003bde738 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
#3 0x00007bd8f5e42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
#4 0x000000000589fc68 llvm::VPlanTransforms::buildPlainCFG(llvm::Loop*, llvm::LoopInfo&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x589fc68)
#5 0x000000000574ceaa llvm::LoopVectorizationPlanner::buildVPlansWithVPRecipes(llvm::ElementCount, llvm::ElementCount) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x574ceaa)
#6 0x000000000574d6a3 llvm::LoopVectorizationPlanner::plan(llvm::ElementCount, unsigned int) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x574d6a3)
I haven't created an IR reproducer yet.