Fold predicable instructions into MOVCC / t2MOVCC.

The ARM select instructions are just predicated moves. If the select is
the only use of an operand, the instruction defining the operand can be
predicated instead, saving one instruction and decreasing register
pressure.

This implementation can turn AND/ORR/EOR instructions into their
corresponding ANDCC/ORRCC/EORCC variants. Ideally, we should be able to
predicate any instruction, but we don't yet support predicated
instructions in SSA form.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161994 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 61 insertions, 1 deletions

diff --git a/test/CodeGen/ARM/select_xform.ll b/test/CodeGen/ARM/select_xform.ll
index ca2e18a639..d98d7a628e 100644
--- a/test/CodeGen/ARM/select_xform.ll
+++ b/test/CodeGen/ARM/select_xform.ll
@@ -104,3 +104,63 @@ entry:
   ret i32 %tmp3
 }
 
+; Fold ORRri into movcc.
+define i32 @t8(i32 %a, i32 %b) nounwind {
+; ARM: t8:
+; ARM: cmp r0, r1
+; ARM: orrge r0, r1, #1
+
+; T2: t8:
+; T2: cmp r0, r1
+; T2: orrge r0, r1, #1
+  %x = or i32 %b, 1
+  %cond = icmp slt i32 %a, %b
+  %tmp1 = select i1 %cond, i32 %a, i32 %x
+  ret i32 %tmp1
+}
+
+; Fold ANDrr into movcc.
+define i32 @t9(i32 %a, i32 %b, i32 %c) nounwind {
+; ARM: t9:
+; ARM: cmp r0, r1
+; ARM: andge r0, r1, r2
+
+; T2: t9:
+; T2: cmp r0, r1
+; T2: andge.w r0, r1, r2
+  %x = and i32 %b, %c
+  %cond = icmp slt i32 %a, %b
+  %tmp1 = select i1 %cond, i32 %a, i32 %x
+  ret i32 %tmp1
+}
+
+; Fold EORrs into movcc.
+define i32 @t10(i32 %a, i32 %b, i32 %c, i32 %d) nounwind {
+; ARM: t10:
+; ARM: cmp r0, r1
+; ARM: eorge r0, r1, r2, lsl #7
+
+; T2: t10:
+; T2: cmp r0, r1
+; T2: eorge.w r0, r1, r2, lsl #7
+  %s = shl i32 %c, 7
+  %x = xor i32 %b, %s
+  %cond = icmp slt i32 %a, %b
+  %tmp1 = select i1 %cond, i32 %a, i32 %x
+  ret i32 %tmp1
+}
+
+; Fold ORRri into movcc, reversing the condition.
+define i32 @t11(i32 %a, i32 %b) nounwind {
+; ARM: t11:
+; ARM: cmp r0, r1
+; ARM: orrlt r0, r1, #1
+
+; T2: t11:
+; T2: cmp r0, r1
+; T2: orrlt r0, r1, #1
+  %x = or i32 %b, 1
+  %cond = icmp slt i32 %a, %b
+  %tmp1 = select i1 %cond, i32 %x, i32 %a
+  ret i32 %tmp1
+}
diff --git a/test/CodeGen/Thumb2/machine-licm.ll b/test/CodeGen/Thumb2/machine-licm.ll
index 82857425a9..01df373232 100644
--- a/test/CodeGen/Thumb2/machine-licm.ll
+++ b/test/CodeGen/Thumb2/machine-licm.ll
@@ -95,7 +95,7 @@ bb.nph:
 bb:                                               ; preds = %bb, %bb.nph
 ; CHECK: bb
 ; CHECK: eor.w
-; CHECK: eor.w {{(r[0-9])|(lr)}}, {{(r[0-9])|(lr)}}, [[REGISTER]]
+; CHECK: eorne.w {{(r[0-9])|(lr)}}, {{(r[0-9])|(lr)}}, [[REGISTER]]
 ; CHECK-NOT: eor
 ; CHECK: and
   %data_addr.013 = phi i8 [ %data, %bb.nph ], [ %8, %bb ] ; <i8> [#uses=2]