diff options
| -rw-r--r-- | clang/lib/CodeGen/README.txt | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/clang/lib/CodeGen/README.txt b/clang/lib/CodeGen/README.txt index ea2cf8cf0ee..e4508c7b82a 100644 --- a/clang/lib/CodeGen/README.txt +++ b/clang/lib/CodeGen/README.txt @@ -28,6 +28,12 @@ In theory, the same optimization could be a win for block local variables as long as the declaration dominates all statements in the block. +NOTE: The main case we care about this for is for -O0 -g compile time +performance, and in that scenario we will need to emit the alloca +anyway currently to emit proper debug info. So this is blocked by +being able to emit debug information which refers to an LLVM +temporary, not an alloca. + //===---------------------------------------------------------------------===// We should try and avoid generating basic blocks which only contain @@ -36,7 +42,7 @@ instruction overhead), all the way down through code generation and assembly time. On 176.gcc:expr.ll, it looks like over 12% of basic blocks are just -direct branches. +direct branches! //===---------------------------------------------------------------------===// |
