Add a DAGCombine for (ext (binop (load x), cst)).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133124 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 36 insertions, 0 deletions

diff --git a/test/CodeGen/X86/zext-fold.ll b/test/CodeGen/X86/zext-fold.ll
new file mode 100644
index 0000000000..f9a5762c02
--- /dev/null
+++ b/test/CodeGen/X86/zext-fold.ll
@@ -0,0 +1,36 @@
+; RUN: llc < %s -march=x86 | FileCheck %s
+
+;; Simple case
+define i32 @test1(i8 %x) nounwind readnone {
+  %A = and i8 %x, -32
+  %B = zext i8 %A to i32
+  ret i32 %B
+}
+; CHECK: test1
+; CHECK: movzbl
+; CHECK-NEXT: andl {{.*}}224
+
+;; Multiple uses of %x but easily extensible. 
+define i32 @test2(i8 %x) nounwind readnone {
+  %A = and i8 %x, -32
+  %B = zext i8 %A to i32
+  %C = or i8 %x, 63
+  %D = zext i8 %C to i32
+  %E = add i32 %B, %D
+  ret i32 %E
+}
+; CHECK: test2
+; CHECK: movzbl
+; CHECK-NEXT: orl {{.*}}63
+; CHECK-NEXT: andl {{.*}}224
+
+declare void @use(i32, i8)
+
+;; Multiple uses of %x where we shouldn't extend the load.
+define void @test3(i8 %x) nounwind readnone {
+  %A = and i8 %x, -32
+  %B = zext i8 %A to i32
+  call void @use(i32 %B, i8 %x)
+  ret void
+}
+; CHECK: test3