instcombine: Migrate memcpy optimizations

This patch migrates the memcpy optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167686 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 34 insertions, 0 deletions

diff --git a/test/Transforms/InstCombine/memcpy-1.ll b/test/Transforms/InstCombine/memcpy-1.ll
new file mode 100644
index 0000000000..65b79ad03d
--- /dev/null
+++ b/test/Transforms/InstCombine/memcpy-1.ll
@@ -0,0 +1,17 @@
+; Test that the memcpy library call simplifier works correctly.
+;
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+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"
+
+declare i8* @memcpy(i8*, i8*, i32)
+
+; Check memcpy(mem1, mem2, size) -> llvm.memcpy(mem1, mem2, size, 1).
+
+define i8* @test_simplify1(i8* %mem1, i8* %mem2, i32 %size) {
+; CHECK: @test_simplify1
+  %ret = call i8* @memcpy(i8* %mem1, i8* %mem2, i32 %size)
+; CHECK: call void @llvm.memcpy
+  ret i8* %ret
+; CHECK: ret i8* %mem1
+}
diff --git a/test/Transforms/InstCombine/memcpy-2.ll b/test/Transforms/InstCombine/memcpy-2.ll
new file mode 100644
index 0000000000..4a8a02018f
--- /dev/null
+++ b/test/Transforms/InstCombine/memcpy-2.ll
@@ -0,0 +1,17 @@
+; Test that the memcpy library call simplifier works correctly.
+;
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+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"
+
+declare i8 @memcpy(i8*, i8*, i32)
+
+; Check that memcpy functions with the wrong prototype aren't simplified.
+
+define i8 @test_no_simplify1(i8* %mem1, i8* %mem2, i32 %size) {
+; CHECK: @test_no_simplify1
+  %ret = call i8 @memcpy(i8* %mem1, i8* %mem2, i32 %size)
+; CHECK: call i8 @memcpy
+  ret i8 %ret
+; CHECK: ret i8 %ret
+}