morehouse added a comment.
Does this hit new coverage in the vectorizer?
================
Comment at: clang/tools/clang-fuzzer/proto-to-llvm/loop_proto_to_llvm.cpp:46
std::string VarRefToString(std::ostream &os, const VarRef &x) {
+ std::string var = inner_loop ? "inner" : "outer";
std::string arr;
----------------
Please choose a better name than var.
================
Comment at: clang/tools/clang-fuzzer/proto-to-llvm/loop_proto_to_llvm.cpp:127
}
+ inner_loop = true;
return os;
----------------
This looks like a bug. `inner_loop` never gets set to false again. Might be a
good reason to make it parameter instead.
================
Comment at: clang/tools/clang-fuzzer/proto-to-llvm/loop_proto_to_llvm.cpp:131
std::ostream &operator<<(std::ostream &os, const LoopFunction &x) {
- return os << "target triple = \"x86_64-unknown-linux-gnu\"\n"
- << "define void @foo(i32* %a, i32* %b, i32* %c, i64 %s) {\n"
- << "%1 = icmp sgt i64 %s, 0\n"
- << "br i1 %1, label %start, label %end\n"
- << "start:\n"
- << "br label %loop\n"
- << "end:\n"
- << "ret void\n"
- << "loop:\n"
- << " %ct = phi i64 [ %ctnew, %loop ], [ 0, %start ]\n"
- << x.statements()
- << "%ctnew = add i64 %ct, 1\n"
- << "%j = icmp eq i64 %ctnew, %s\n"
- << "br i1 %j, label %end, label %loop, !llvm.loop !0\n}\n"
- << "!0 = distinct !{!0, !1, !2}\n"
- << "!1 = !{!\"llvm.loop.vectorize.enable\", i1 true}\n"
- << "!2 = !{!\"llvm.loop.vectorize.width\", i32 " << kArraySize
- << "}\n";
+ os << "target triple = \"x86_64-pc-linux-gnu\"\n"
+ << "define void @foo(i32* %a, i32* %b, i32* noalias %c, i64 %s) {\n"
----------------
Why do you change this to `pc` again?
================
Comment at: clang/tools/clang-fuzzer/proto-to-llvm/loop_proto_to_llvm.cpp:132
+ os << "target triple = \"x86_64-pc-linux-gnu\"\n"
+ << "define void @foo(i32* %a, i32* %b, i32* noalias %c, i64 %s) {\n"
+ << "%cmp = icmp sgt i64 %s, 0\n"
----------------
I'm curious how this change affects coverage independent of the rest of this
change. Also what would happen if we set `%a` and `%b` to noalias as well?
================
Comment at: clang/tools/clang-fuzzer/proto-to-llvm/loop_proto_to_llvm.cpp:136
+ << "outer_loop_start:\n"
+ << "br label %inner_loop_start\n"
+ << "inner_loop_start:\n"
----------------
Looks like a pointless branch.
================
Comment at: clang/tools/clang-fuzzer/proto-to-llvm/loop_proto_to_llvm.cpp:144
+ << x.outer_statements()
+ << "%o_ct_new = add nuw nsw i64 %outer_ct, 1\n"
+ << "%jmp_outer = icmp eq i64 %o_ct_new, %s\n"
----------------
Why `nuw`, `nsw` here?
================
Comment at: clang/tools/clang-fuzzer/proto-to-llvm/loop_proto_to_llvm.cpp:154
+ << "}\n"
+ << "!0 = distinct !{!0, !1, !2}\n"
+ << "!1 = !{!\"llvm.loop.vectorize.enable\", i1 true}\n"
----------------
Can we simplify the order of blocks here? It is confusing to follow all these
jumps forward and backward.
Repository:
rC Clang
https://reviews.llvm.org/D50670
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