Also combine zext/sext into selects for ARM.

This turns common i1 patterns into predicated instructions:

  (add (zext cc), x) -> (select cc (add x, 1), x)
  (add (sext cc), x) -> (select cc (add x, -1), x)

For a function like:

  unsigned f(unsigned s, int x) {
    return s + (x>0);
  }

We now produce:

  cmp r1, #0
  it  gt
  addgt.w r0, r0, #1

Instead of:

  movs  r2, #0
  cmp r1, #0
  it  gt
  movgt r2, #1
  add r0, r2

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162177 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 32 insertions, 0 deletions

diff --git a/test/CodeGen/ARM/select_xform.ll b/test/CodeGen/ARM/select_xform.ll
index c4b07326dd..cfc0e70120 100644
--- a/test/CodeGen/ARM/select_xform.ll
+++ b/test/CodeGen/ARM/select_xform.ll
@@ -190,3 +190,35 @@ define void @pr13628() nounwind uwtable align 2 {
   ret void
 }
 declare void @bar(i8*)
+
+; Fold zext i1 into predicated add
+define i32 @t13(i32 %c, i32 %a) nounwind readnone ssp {
+entry:
+; ARM: t13
+; ARM: cmp r1, #10
+; ARM: addgt r0, r0, #1
+
+; T2: t13
+; T2: cmp r1, #10
+; T2: addgt.w r0, r0, #1
+  %cmp = icmp sgt i32 %a, 10
+  %conv = zext i1 %cmp to i32
+  %add = add i32 %conv, %c
+  ret i32 %add
+}
+
+; Fold sext i1 into predicated sub
+define i32 @t14(i32 %c, i32 %a) nounwind readnone ssp {
+entry:
+; ARM: t14
+; ARM: cmp r1, #10
+; ARM: subgt r0, r0, #1
+
+; T2: t14
+; T2: cmp r1, #10
+; T2: subgt.w r0, r0, #1
+  %cmp = icmp sgt i32 %a, 10
+  %conv = sext i1 %cmp to i32
+  %add = add i32 %conv, %c
+  ret i32 %add
+}