From 163162a0a41213ce6ca052f6ab5822669d2391ac Mon Sep 17 00:00:00 2001
From: Chen Zheng <czhengsz@cn.ibm.com>
Date: Sun, 14 Jun 2020 21:22:50 -0400
Subject: [PATCH] [PowerPC] fold a bug for rlwinm folding when with full mask.

Reviewed By: steven.zhang

Differential Revision: https://reviews.llvm.org/D81006
---
 llvm/lib/Target/PowerPC/PPCInstrInfo.cpp  |  3 +--
 llvm/test/CodeGen/PowerPC/fold-rlwinm.mir | 14 ++++++++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp b/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
index 457f4c1aa85b..e70f04e72ed5 100644
--- a/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
+++ b/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
@@ -3421,8 +3421,7 @@ bool PPCInstrInfo::simplifyToLI(MachineInstr &MI, MachineInstr &DefMI,
     int64_t ME = MI.getOperand(4).getImm();
     APInt InVal(32, SExtImm, true);
     InVal = InVal.rotl(SH);
-    // Set the bits (        MB + 32        ) to (        ME + 32        ).
-    uint64_t Mask = ((1LLU << (32 - MB)) - 1) & ~((1LLU << (31 - ME)) - 1);
+    APInt Mask = APInt::getBitsSetWithWrap(32, 32 - ME - 1, 32 - MB);
     InVal &= Mask;
     // Can't replace negative values with an LI as that will sign-extend
     // and not clear the left bits. If we're setting the CR bit, we will use
diff --git a/llvm/test/CodeGen/PowerPC/fold-rlwinm.mir b/llvm/test/CodeGen/PowerPC/fold-rlwinm.mir
index dc69dcb11d25..ded5329a46cc 100644
--- a/llvm/test/CodeGen/PowerPC/fold-rlwinm.mir
+++ b/llvm/test/CodeGen/PowerPC/fold-rlwinm.mir
@@ -168,3 +168,17 @@ body: |
     ; CHECK: %3:gprc = RLWINM %2, 19, 10, 20
     BLR8 implicit $lr8, implicit $rm
 ...
+---
+name: testFoldRLWINMLIWrapMask
+#CHECK: name: testFoldRLWINMLIWrapMask
+tracksRegLiveness: true
+body: |
+  bb.0.entry:
+    liveins: $x3
+    %0:gprc = COPY $x3
+    %1:gprc = LI 100
+    ; CHECK: %2:gprc = LI 200
+    %2:gprc = RLWINM %1:gprc, 1, 3, 2
+    STW %2:gprc, %0:gprc, 100
+    BLR8 implicit $lr8, implicit $rm
+...