From 3875cb60f32067943dfb82a71b5212dab3969cdc Mon Sep 17 00:00:00 2001
From: Richard Sandiford <rsandifo@linux.vnet.ibm.com>
Date: Thu, 9 Jan 2014 11:28:53 +0000
Subject: [PATCH] [SystemZ] Fix RNSBG bug introduced by r197802

The zext handling added in r197802 wasn't right for RNSBG.  This patch
restricts it to ROSBG, RXSBG and RISBG.  (The tests for RISBG were added
in r197802 since RISBG was the motivating example.)

llvm-svn: 198862
---
 llvm/lib/Target/SystemZ/SystemZISelDAGToDAG.cpp | 18 ++++++++++--------
 llvm/test/CodeGen/SystemZ/rnsbg-01.ll           | 11 +++++++++++
 llvm/test/CodeGen/SystemZ/rosbg-01.ll           | 11 +++++++++++
 llvm/test/CodeGen/SystemZ/rxsbg-01.ll           | 11 +++++++++++
 4 files changed, 43 insertions(+), 8 deletions(-)

diff --git a/llvm/lib/Target/SystemZ/SystemZISelDAGToDAG.cpp b/llvm/lib/Target/SystemZ/SystemZISelDAGToDAG.cpp
index d95361e..aa4752c 100644
--- a/llvm/lib/Target/SystemZ/SystemZISelDAGToDAG.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZISelDAGToDAG.cpp
@@ -769,15 +769,17 @@ bool SystemZDAGToDAGISel::expandRxSBG(RxSBGOperands &RxSBG) const {
     RxSBG.Input = N.getOperand(0);
     return true;
 
-  case ISD::ZERO_EXTEND: {
-    // Restrict the mask to the extended operand.
-    unsigned InnerBitSize = N.getOperand(0).getValueType().getSizeInBits();
-    if (!refineRxSBGMask(RxSBG, allOnes(InnerBitSize)))
-      return false;
+  case ISD::ZERO_EXTEND:
+    if (RxSBG.Opcode != SystemZ::RNSBG) {
+      // Restrict the mask to the extended operand.
+      unsigned InnerBitSize = N.getOperand(0).getValueType().getSizeInBits();
+      if (!refineRxSBGMask(RxSBG, allOnes(InnerBitSize)))
+        return false;
 
-    RxSBG.Input = N.getOperand(0);
-    return true;
-  }
+      RxSBG.Input = N.getOperand(0);
+      return true;
+    }
+    // Fall through.
     
   case ISD::SIGN_EXTEND: {
     // Check that the extension bits are don't-care (i.e. are masked out
diff --git a/llvm/test/CodeGen/SystemZ/rnsbg-01.ll b/llvm/test/CodeGen/SystemZ/rnsbg-01.ll
index 666aeb2..282810a 100644
--- a/llvm/test/CodeGen/SystemZ/rnsbg-01.ll
+++ b/llvm/test/CodeGen/SystemZ/rnsbg-01.ll
@@ -255,3 +255,14 @@ define i64 @f22(i64 %a, i64 %b) {
   %and = and i64 %a, %rotlorb
   ret i64 %and
 }
+
+; Check the handling of zext and AND, which isn't suitable for RNSBG.
+define i64 @f23(i64 %a, i32 %b) {
+; CHECK-LABEL: f23:
+; CHECK-NOT: rnsbg
+; CHECK: br %r14
+  %add = add i32 %b, 1
+  %ext = zext i32 %add to i64
+  %and = and i64 %a, %ext
+  ret i64 %and
+}
diff --git a/llvm/test/CodeGen/SystemZ/rosbg-01.ll b/llvm/test/CodeGen/SystemZ/rosbg-01.ll
index 0abaccc..96ee870 100644
--- a/llvm/test/CodeGen/SystemZ/rosbg-01.ll
+++ b/llvm/test/CodeGen/SystemZ/rosbg-01.ll
@@ -108,3 +108,14 @@ define i64 @f11(i64 %a, i64 %b) {
   %or = or i64 %a, %andb
   ret i64 %or
 }
+
+; Check the handling of zext and OR, which can use ROSBG.
+define i64 @f12(i64 %a, i32 %b) {
+; CHECK-LABEL: f12:
+; CHECK: rosbg %r2, %r3, 32, 63, 0
+; CHECK: br %r14
+  %add = add i32 %b, 1
+  %ext = zext i32 %add to i64
+  %or = or i64 %a, %ext
+  ret i64 %or
+}
diff --git a/llvm/test/CodeGen/SystemZ/rxsbg-01.ll b/llvm/test/CodeGen/SystemZ/rxsbg-01.ll
index 5491bff..339fe2a 100644
--- a/llvm/test/CodeGen/SystemZ/rxsbg-01.ll
+++ b/llvm/test/CodeGen/SystemZ/rxsbg-01.ll
@@ -110,3 +110,14 @@ define i64 @f11(i64 %a, i64 %b) {
   %xor = xor i64 %a, %andb
   ret i64 %xor
 }
+
+; Check the handling of zext and XOR, which can use ROSBG.
+define i64 @f12(i64 %a, i32 %b) {
+; CHECK-LABEL: f12:
+; CHECK: rxsbg %r2, %r3, 32, 63, 0
+; CHECK: br %r14
+  %add = add i32 %b, 1
+  %ext = zext i32 %add to i64
+  %xor = xor i64 %a, %ext
+  ret i64 %xor
+}
-- 
2.7.4