[PATCH] R600: Correctly handle vertex fetch clauses the precede ENDIFs

[Tom Stellard]

From: Tom Stellard <thomas.stellard at amd.com>

The control flow finalizer would sometimes use an ALU_POP_AFTER
instruction before the vetex fetch clause instead of using a POP
instruction after it.
---
 lib/Target/R600/R600ControlFlowFinalizer.cpp |  1 +
 test/CodeGen/R600/vtx-fetch-branch.ll        | 29 ++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 test/CodeGen/R600/vtx-fetch-branch.ll

diff --git a/lib/Target/R600/R600ControlFlowFinalizer.cpp b/lib/Target/R600/R600ControlFlowFinalizer.cpp
index ec39e09..bca243c 100644
--- a/lib/Target/R600/R600ControlFlowFinalizer.cpp
+++ b/lib/Target/R600/R600ControlFlowFinalizer.cpp
@@ -357,6 +357,7 @@ public:
           DEBUG(dbgs() << CfCount << ":"; I->dump(););
           FetchClauses.push_back(MakeFetchClause(MBB, I));
           CfCount++;
+          LastAlu.back() = 0;
           continue;
         }
 
diff --git a/test/CodeGen/R600/vtx-fetch-branch.ll b/test/CodeGen/R600/vtx-fetch-branch.ll
new file mode 100644
index 0000000..0fc99de
--- /dev/null
+++ b/test/CodeGen/R600/vtx-fetch-branch.ll
@@ -0,0 +1,29 @@
+; RUN: llc -march=r600 -mcpu=redwood %s -o - | FileCheck %s
+
+; This tests for a bug where vertex fetch clauses right before an ENDIF
+; instruction where being emitted after the ENDIF.  We were using ALU_POP_AFTER
+; for the ALU clause before the vetex fetch instead of emitting a POP instruction
+; after the fetch clause.
+
+
+; CHECK-LABEL: @test
+; CHECK-NOT: ALU_POP_AFTER
+; CHECK: TEX
+; CHECK-NEXT: POP
+define void @test(i32 addrspace(1)* %out, i32 addrspace(1)* %in, i32 %cond) {
+entry:
+  %0 = icmp eq i32 %cond, 0
+  br i1 %0, label %endif, label %if
+
+if:
+  %1 = load i32 addrspace(1)* %in
+  br label %endif
+
+endif:
+  %x = phi i32 [ %1, %if], [ 0, %entry]
+  store i32 %x, i32 addrspace(1)* %out
+  br label %done
+
+done:
+  ret void
+}
-- 
1.8.1.4