6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-08-17 21:29:20 +00:00
Code Issues Projects Releases Wiki Activity

add a note

Browse Source 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57557 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-10-15 05:53:25 +00:00
parent 241ab47ac1
commit b7fe708b32
1 changed files with 30 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
lib/Target/README.txt
View File

@ -891,3 +891,33 @@ vec2d foo () {
}
//===---------------------------------------------------------------------===//
This C++ file:
void g(); struct A { int n; int m; A& operator++(void) { ++n; if (n == m) g();
return *this; } A() : n(0), m(0) { } friend bool operator!=(A const& a1,
A const& a2) { return a1.n != a2.n; } }; void testfunction(A& iter) { A const
end; while (iter != end) ++iter; }
Compiles down to:
bb: ; preds = %bb3.backedge, %bb.nph
%.rle = phi i32 [ %1, %bb.nph ], [ %7, %bb3.backedge ] ; <i32> [#uses=1]
%4 = add i32 %.rle, 1 ; <i32> [#uses=2]
store i32 %4, i32* %0, align 4
%5 = load i32* %3, align 4 ; <i32> [#uses=1]
%6 = icmp eq i32 %4, %5 ; <i1> [#uses=1]
br i1 %6, label %bb1, label %bb3.backedge
bb1: ; preds = %bb
tail call void @_Z1gv()
br label %bb3.backedge
bb3.backedge: ; preds = %bb, %bb1
%7 = load i32* %0, align 4 ; <i32> [#uses=2]
The %7 load is partially redundant with the store of %4 to %0, GVN's PRE
should remove it, but it doesn't apply to memory objects.
//===---------------------------------------------------------------------===//