$ clang-trunk -v clang version 4.0.0 (trunk 278233) Target: x86_64-unknown-linux-gnu Thread model: posix InstalledDir: /usr/local/bin Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5 Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5.3.0 Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8 Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8.5 Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9 Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9.2 Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9.3 Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5 Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.3.0 Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8 Candidate multilib: .;@m64 Candidate multilib: 32;@m32 Candidate multilib: x32;@mx32 Selected multilib: .;@m64 $ clang-trunk -Os small.c clang-4.0: /tmp/llvm-builder/llvm-source-trunk/lib/Analysis/ScalarEvolution.cpp:1407: const llvm::SCEV* llvm::ScalarEvolution::getZeroExtendExpr(const llvm::SCEV*, llvm::Type*): Assertion `getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && "This is not an extending conversion!"' failed. #0 0x0000000001c22da5 llvm::sys::PrintStackTrace(llvm::raw_ostream&) (/usr/local/clang-trunk/bin/clang-4.0+0x1c22da5) #1 0x0000000001c20d0e llvm::sys::RunSignalHandlers() (/usr/local/clang-trunk/bin/clang-4.0+0x1c20d0e) #2 0x0000000001c20e72 SignalHandler(int) (/usr/local/clang-trunk/bin/clang-4.0+0x1c20e72) #3 0x00007fe050527330 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x10330) #4 0x00007fe04f318c37 gsignal /build/eglibc-oGUzwX/eglibc-2.19/signal/../nptl/sysdeps/unix/sysv/linux/raise.c:56:0 #5 0x00007fe04f31c028 abort /build/eglibc-oGUzwX/eglibc-2.19/stdlib/abort.c:91:0 #6 0x00007fe04f311bf6 __assert_fail_base /build/eglibc-oGUzwX/eglibc-2.19/assert/assert.c:92:0 #7 0x00007fe04f311ca2 (/lib/x86_64-linux-gnu/libc.so.6+0x2fca2) #8 0x00000000014faf7c llvm::ScalarEvolution::getZeroExtendExpr(llvm::SCEV const*, llvm::Type*) (/usr/local/clang-trunk/bin/clang-4.0+0x14faf7c) #9 0x0000000001ad67d2 (anonymous namespace)::IndVarSimplify::run(llvm::Loop*) [clone .part.454] (/usr/local/clang-trunk/bin/clang-4.0+0x1ad67d2) #10 0x0000000001ad93d9 (anonymous namespace)::IndVarSimplifyLegacyPass::runOnLoop(llvm::Loop*, llvm::LPPassManager&) [clone .part.455] (/usr/local/clang-trunk/bin/clang-4.0+0x1ad93d9) #11 0x0000000002492b5f llvm::LPPassManager::runOnFunction(llvm::Function&) (/usr/local/clang-trunk/bin/clang-4.0+0x2492b5f) #12 0x00000000018a5763 llvm::FPPassManager::runOnFunction(llvm::Function&) (/usr/local/clang-trunk/bin/clang-4.0+0x18a5763) #13 0x0000000002471bc0 (anonymous namespace)::CGPassManager::runOnModule(llvm::Module&) (/usr/local/clang-trunk/bin/clang-4.0+0x2471bc0) #14 0x00000000018a5dff llvm::legacy::PassManagerImpl::run(llvm::Module&) (/usr/local/clang-trunk/bin/clang-4.0+0x18a5dff) #15 0x0000000001d7bea0 clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::DataLayout const&, llvm::Module*, clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream> >) (/usr/local/clang-trunk/bin/clang-4.0+0x1d7bea0) #16 0x00000000023716e8 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/usr/local/clang-trunk/bin/clang-4.0+0x23716e8) #17 0x00000000026c419b clang::ParseAST(clang::Sema&, bool, bool) (/usr/local/clang-trunk/bin/clang-4.0+0x26c419b) #18 0x0000000002371ade clang::CodeGenAction::ExecuteAction() (/usr/local/clang-trunk/bin/clang-4.0+0x2371ade) #19 0x000000000208ee46 clang::FrontendAction::Execute() (/usr/local/clang-trunk/bin/clang-4.0+0x208ee46) #20 0x0000000002069e4e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/usr/local/clang-trunk/bin/clang-4.0+0x2069e4e) #21 0x0000000002114946 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/usr/local/clang-trunk/bin/clang-4.0+0x2114946) #22 0x0000000000a52ee8 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/usr/local/clang-trunk/bin/clang-4.0+0xa52ee8) #23 0x00000000009fdbcf main (/usr/local/clang-trunk/bin/clang-4.0+0x9fdbcf) #24 0x00007fe04f303f45 __libc_start_main /build/eglibc-oGUzwX/eglibc-2.19/csu/libc-start.c:321:0 #25 0x0000000000a4ed9d _start (/usr/local/clang-trunk/bin/clang-4.0+0xa4ed9d) Stack dump: 0. Program arguments: /usr/local/clang-trunk/bin/clang-4.0 -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -disable-free -main-file-name small.c -mrelocation-model static -mthread-model posix -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -momit-leaf-frame-pointer -dwarf-column-info -debugger-tuning=gdb -resource-dir /usr/local/clang-trunk/bin/../lib/clang/4.0.0 -c-isystem . -c-isystem /usr/local/include/csmith-2.2.0/ -c-isystem /usr/local/include/csmith-2.2.0/ -internal-isystem /usr/local/include -internal-isystem /usr/local/clang-trunk/bin/../lib/clang/4.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -Os -fdebug-compilation-dir /home/cnsun/ramdisk/hermes/run-2/res/20160810-clang-trunk-m64-g-O3-build-134704/delta -ferror-limit 19 -fmessage-length 118 -fobjc-runtime=gcc -fdiagnostics-show-option -fcolor-diagnostics -vectorize-loops -vectorize-slp -o /tmp/small-fba2b9.o -x c small.c 1. <eof> parser at end of file 2. Per-module optimization passes 3. Running pass 'CallGraph Pass Manager' on module 'small.c'. 4. Running pass 'Loop Pass Manager' on function '@fn2' 5. Running pass 'Induction Variable Simplification' on basic block '%for.cond' clang-4.0: error: unable to execute command: Aborted (core dumped) clang-4.0: error: clang frontend command failed due to signal (use -v to see invocation) clang version 4.0.0 (trunk 278233) Target: x86_64-unknown-linux-gnu Thread model: posix InstalledDir: /usr/local/bin clang-4.0: note: diagnostic msg: PLEASE submit a bug report to http://llvm.org/bugs/ and include the crash backtrace, preprocessed source, and associated run script. clang-4.0: note: diagnostic msg: ******************** PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT: Preprocessed source(s) and associated run script(s) are located at: clang-4.0: note: diagnostic msg: /tmp/small-6e2525.c clang-4.0: note: diagnostic msg: /tmp/small-6e2525.sh clang-4.0: note: diagnostic msg: ******************** $ cat small.c int a; char d; unsigned short fn1(unsigned short, long long); static char fn2(p1) { char e; int f; for (;; f++) { e = fn1(f, f); d = e << a; } } unsigned short fn1(unsigned short p1, long long p2) { fn2(p2); return p1; } $
It's -indvars, reduced IR: target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" target triple = "x86_64-unknown-linux-gnu" @a = external global i32, align 4 @d = external global i8, align 1 declare zeroext i16 @fn1(i16 returned zeroext, i64) define internal void @fn2() { entry: br label %for.cond for.cond: ; preds = %for.cond, %entry %f.0 = phi i32 [ undef, %entry ], [ %inc, %for.cond ] %conv = trunc i32 %f.0 to i16 %conv1 = sext i32 %f.0 to i64 %call = tail call zeroext i16 @fn1(i16 zeroext %conv, i64 %conv1) %conv2 = zext i16 %call to i32 %inc = add nsw i32 %f.0, 1 br label %for.cond }
reduced further: target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" target triple = "x86_64-unknown-linux-gnu" declare i16 @fn1(i16 returned, i64) define void @fn2() { entry: br label %for.cond for.cond: ; preds = %for.cond, %entry %f.0 = phi i64 [ undef, %entry ], [ %inc, %for.cond ] %conv = trunc i64 %f.0 to i16 %call = tail call i16 @fn1(i16 %conv, i64 %f.0) %conv2 = zext i16 %call to i32 %inc = add nsw i64 %f.0, 1 br label %for.cond }
Looks like a 3.8 -> 3.9 regression. David, are you looking at this at the moment? Otherwise I'll start bisecting.
(In reply to comment #3) > Looks like a 3.8 -> 3.9 regression. > > David, are you looking at this at the moment? Otherwise I'll start bisecting. I've bisected it already, it has to do with inference of 'returned'. I've asked Sanjoy to take a look at this one.
Should be fixed in 278584