Displaying 1 result from an estimated 1 matches for "f036ca8b".
2016 Jan 30
2
Redundant promotion of integer values in x86 target
Hello,
While looking at some internal benchmarks, I found that llvm generates codes with redundant promotion, something like:
xor %al, %cl
movzbl %cl, %ecx
cmp $0x20, %ecx
I believe that the promotion stems from the logic in X86TargetLowering::EmitCmp. Comments in the code says,
"Do the comparison at i32 if it's smaller, besides the Atom case. This avoids subregister aliasing issues.