Prevent folding of a node with multiple uses if the node already folds a load!
Here is an example where the load ended up being done twice:
%A = global uint 0
uint %test(uint %B, ubyte %C) {
%tmp = load uint *%A;
%X = shl uint %tmp, ubyte %C
%Cv = sub ubyte 32, %C
%Y = shr uint %B, ubyte %Cv
%Z = or uint %Y, %X
store uint %Z, uint* %A
ret uint %Z
}
==>
subl $4, %esp
movl %ebx, (%esp)
movl 8(%esp), %edx
movl A, %eax
movb 12(%esp), %bl
movb %bl, %cl
shldl %cl, %edx, %eax
movb %bl, %cl
shldl %cl, %edx, A
movl (%esp), %ebx
addl $4, %esp
ret
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@25471 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed