Implement major new fastisel functionality: the matcher can now handle immediates with
value constraints on them (when defined as ImmLeaf's). This is particularly important
for X86-64, where almost all reg/imm instructions take a i64immSExt32 immediate operand,
which has a value constraint. Before this patch we ended up iseling the examples into
such amazing code as:
movabsq $7, %rax
imulq %rax, %rdi
movq %rdi, %rax
ret
now we produce:
imulq $7, %rdi, %rax
ret
This dramatically shrinks the generated code at -O0 on x86-64.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129691 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed