search for: r122603

...} > > I find it strange that it hasn't found that %add and %mul have the same value, %cmp would be then false, selecting and returning 15. If 'a' is replaced by a constant it works. You're right, that is a missed optimization. I added it to the missed optimization notes in r122603. Did this come from a larger example, or was this just a test? > I'm also curios which pass detects that c[10] and c[11] are 'a' in 'b = c[10] + c[11]' (it isn't instcombine, at -O1 getelementptr/load are still there). There are several capable of picking this up, but...

...gt; I find it strange that it hasn't found that %add and %mul have the same value, %cmp would be then false, selecting and returning 15. If 'a' is replaced by a constant it works. > > You're right, that is a missed optimization. I added it to the missed optimization notes in r122603. Did this come from a larger example, or was this just a test? Just as a note, if you run this example through the opt tool as well then the output is the expected "ret i32 15". > clang -O3 -S -emit-llvm -o - example.c |opt -std-compile-opts -o - |llvm-dis target datalayout = &q...

I recently downloaded LLVM 2.8 and started playing with the optimizations a bit. I saw something curious while trying the following function: int g(unsigned int a) { unsigned int c[100]; c[10] = a; c[11] = a; unsigned int b = c[10] + c[11]; if(b > a*2) a = 4; else a = 8; return a + 7; } The generated code, with -O3 activated, is define i32 @g(i32 a) nounwind readnone { %add = shl i32