[LLVMdev] MI scheduler produce badly code with inline function

[Zakk]

Hi all,
I meet this problem when compiling the TREAM benchmark (
http://www.cs.virginia.edu/stream/FTP/Code/) with enable-misched

The small function will be scheduled as good code, but if opt inline this
function, the inline part will be scheduled as bad code.

so I rewrite a simple code as attached link (foo.c), and compiled with two
different methods:

*method A:*
*$clang -O3 foo.c -static -S -o foo.s -mllvm -enable-misched  -mllvm
-unroll-count=4 --target=arm -mfloat-abi=hard -mcpu=cortex-a9
-fno-vectorize -fno-slp-vectorize*
*
*
*and*
*
*
*method B:*
*$clang foo.c -S -emit-llvm -o foo.bc --target=arm -mfloat-abi=hard
-mcpu=cortex-a9
*

*$opt foo.bc -O3 -unroll-count=4 -o foo.opt.bc*
* *

*$llc foo.opt.bc -o foo.opt.s -march=arm -mcpu=cortex-a9 -enable-misched*


(ps. I had checked with debug-pass=structure, so I think they are
equivalently)


but the result is different:

You can find the LBB1_4 of foo.s, it always reuses the same reg for
computation, but LBB1_4 of foo.opt.s doesn't.


My question is how to just use clang (method A) to achieve B result?
Or i am missing something here?


I really appreciate any help and suggestions.

Thanks


Kuan-Hsu

------- file link -------

foo.c: http://goo.gl/nVa2K0
foo.s: http://goo.gl/ML9eNj
foo.opt.s: http://goo.gl/31PCnf
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