diff options
| -rw-r--r-- | lib/Target/README.txt | 29 | ||||
| -rw-r--r-- | test/Transforms/GVN/lpre-call-wrap.ll | 54 |
2 files changed, 54 insertions, 29 deletions
diff --git a/lib/Target/README.txt b/lib/Target/README.txt index e0cab2a..c19fd9c 100644 --- a/lib/Target/README.txt +++ b/lib/Target/README.txt @@ -1404,32 +1404,3 @@ void foo (int a, struct T b) //===---------------------------------------------------------------------===// -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. - -//===---------------------------------------------------------------------===// - diff --git a/test/Transforms/GVN/lpre-call-wrap.ll b/test/Transforms/GVN/lpre-call-wrap.ll new file mode 100644 index 0000000..7afa6fd --- /dev/null +++ b/test/Transforms/GVN/lpre-call-wrap.ll @@ -0,0 +1,54 @@ +; RUN: llvm-as < %s | opt -gvn -enable-load-pre | llvm-dis > %t +; RUN: %prcontext bb3.backedge: 2 < %t | grep phi +; RUN: %prcontext bb3.backedge: 2 < %t | not grep load +; +; Make sure the load in bb3.backedge is removed and moved into bb1 after the +; call. This makes the non-call case faster. +; +; This test is derived from this C++ code: +; 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; } +; +target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128" +target triple = "i386-apple-darwin7" + %struct.A = type { i32, i32 } + +define void @_Z12testfunctionR1A(%struct.A* %iter) { +entry: + %0 = getelementptr %struct.A* %iter, i32 0, i32 0 ; <i32*> [#uses=3] + %1 = load i32* %0, align 4 ; <i32> [#uses=2] + %2 = icmp eq i32 %1, 0 ; <i1> [#uses=1] + br i1 %2, label %return, label %bb.nph + +bb.nph: ; preds = %entry + %3 = getelementptr %struct.A* %iter, i32 0, i32 1 ; <i32*> [#uses=1] + br label %bb + +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] + %8 = icmp eq i32 %7, 0 ; <i1> [#uses=1] + br i1 %8, label %return, label %bb + +return: ; preds = %bb3.backedge, %entry + ret void +} + +declare void @_Z1gv() |