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

2 files changed, 48 insertions, 2 deletions

diff --git a/test/CodeGen/X86/promote-i16.ll b/test/CodeGen/X86/promote-i16.ll
index 101bb29..a785daf 100644
--- a/test/CodeGen/X86/promote-i16.ll
+++ b/test/CodeGen/X86/promote-i16.ll
@@ -3,9 +3,19 @@
 define signext i16 @foo(i16 signext %x) nounwind {
 entry:
 ; CHECK: foo:
-; CHECK: movzwl 4(%esp), %eax
-; CHECK: xorl $21998, %eax
+; CHECK-NOT: movzwl
 ; CHECK: movswl %ax, %eax
+; CHECK: xorl $21998, %eax
   %0 = xor i16 %x, 21998
   ret i16 %0
 }
+
+define signext i16 @bar(i16 signext %x) nounwind {
+entry:
+; CHECK: bar:
+; CHECK-NOT: movzwl
+; CHECK: movswl %ax, %eax
+; CHECK: xorl $-10770, %eax
+  %0 = xor i16 %x, 54766
+  ret i16 %0
+}
diff --git a/test/CodeGen/X86/zext-fold.ll b/test/CodeGen/X86/zext-fold.ll
new file mode 100644
index 0000000..f9a5762
--- /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