SelectionDAG: Select min/max when both are used

Allow two users of the condition if the other user
is also a min/max select. i.e.

%c = icmp slt i32 %x, %y
%min = select i1 %c, i32 %x, i32 %y
%max = select i1 %c, i32 %y, i32 %x

llvm-svn: 269699

1 files changed, 13 insertions, 1 deletions

diff --git a/llvm/test/CodeGen/AMDGPU/select-i1.ll b/llvm/test/CodeGen/AMDGPU/select-i1.ll
index 6735394e93a..2406831b94c 100644
--- a/llvm/test/CodeGen/AMDGPU/select-i1.ll
+++ b/llvm/test/CodeGen/AMDGPU/select-i1.ll
@@ -1,4 +1,4 @@
-; RUN: llc -march=amdgcn -mcpu=SI -verify-machineinstrs < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
+; RUN: llc -march=amdgcn -verify-machineinstrs < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
 ; RUN: llc -march=amdgcn -mcpu=tonga -verify-machineinstrs < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
 
 ; FIXME: This should go in existing select.ll test, except the current testcase there is broken on SI
@@ -13,3 +13,15 @@ define void @select_i1(i1 addrspace(1)* %out, i32 %cond, i1 %a, i1 %b) nounwind
   ret void
 }
 
+; FUNC-LABEL: {{^}}s_minmax_i1:
+; SI-DAG: buffer_load_ubyte [[COND:v[0-9]+]], off, s{{\[[0-9]+:[0-9]+\]}}, 0 offset:44
+; SI-DAG: buffer_load_ubyte [[A:v[0-9]+]], off, s{{\[[0-9]+:[0-9]+\]}}, 0 offset:45
+; SI-DAG: buffer_load_ubyte [[B:v[0-9]+]], off, s{{\[[0-9]+:[0-9]+\]}}, 0 offset:46
+; SI: v_cmp_eq_i32_e32 vcc, 1, [[COND]]
+; SI: v_cndmask_b32_e32 v{{[0-9]+}}, [[B]], [[A]]
+define void @s_minmax_i1(i1 addrspace(1)* %out, i1 zeroext %cond, i1 zeroext %a, i1 zeroext %b) nounwind {
+  %cmp = icmp slt i1 %cond, false
+  %sel = select i1 %cmp, i1 %a, i1 %b
+  store i1 %sel, i1 addrspace(1)* %out, align 4
+  ret void
+}