[llvm] e887d0e - [AArch64][GlobalISel] Handle rtcGPR64RegClassID in AArch64RegisterBankInfo::getRegBankFromRegClass()

[Jessica Paquette via llvm-commits]

Author: Raul Tambre
Date: 2020-08-19T12:52:30-07:00
New Revision: e887d0e89b837be37b4279735a9c1ac57e90c995

URL: https://github.com/llvm/llvm-project/commit/e887d0e89b837be37b4279735a9c1ac57e90c995
DIFF: https://github.com/llvm/llvm-project/commit/e887d0e89b837be37b4279735a9c1ac57e90c995.diff

LOG: [AArch64][GlobalISel] Handle rtcGPR64RegClassID in AArch64RegisterBankInfo::getRegBankFromRegClass()

TargetRegisterInfo::getMinimalPhysRegClass() returns rtcGPR64RegClassID for X16
and X17, as it's the last matching class. This in turn gets passed to
AArch64RegisterBankInfo::getRegBankFromRegClass(), which hits an unreachable.

It seems sensible to handle this case, so copies from X16 and X17 work.
Copying from X17 is used in inline assembly in libunwind for pointer
authentication.

Differential Revision: https://reviews.llvm.org/D85720

Added: 
    

Modified: 
    llvm/lib/Target/AArch64/GISel/AArch64RegisterBankInfo.cpp
    llvm/test/CodeGen/AArch64/GlobalISel/regbankselect-default.mir

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/AArch64/GISel/AArch64RegisterBankInfo.cpp b/llvm/lib/Target/AArch64/GISel/AArch64RegisterBankInfo.cpp
index 7e3ff1948dad..93213f5977e5 100644
--- a/llvm/lib/Target/AArch64/GISel/AArch64RegisterBankInfo.cpp
+++ b/llvm/lib/Target/AArch64/GISel/AArch64RegisterBankInfo.cpp
@@ -261,6 +261,7 @@ AArch64RegisterBankInfo::getRegBankFromRegClass(const TargetRegisterClass &RC,
   case AArch64::GPR64common_and_GPR64noipRegClassID:
   case AArch64::GPR64noip_and_tcGPR64RegClassID:
   case AArch64::tcGPR64RegClassID:
+  case AArch64::rtcGPR64RegClassID:
   case AArch64::WSeqPairsClassRegClassID:
   case AArch64::XSeqPairsClassRegClassID:
     return getRegBank(AArch64::GPRRegBankID);

diff  --git a/llvm/test/CodeGen/AArch64/GlobalISel/regbankselect-default.mir b/llvm/test/CodeGen/AArch64/GlobalISel/regbankselect-default.mir
index e226c0fbae7d..09884c75409e 100644
--- a/llvm/test/CodeGen/AArch64/GlobalISel/regbankselect-default.mir
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/regbankselect-default.mir
@@ -75,6 +75,8 @@
 
   define void @test_gphi_ptr() { ret void }
 
+  define void @test_restricted_tail_call() { ret void }
+
 ...
 
 ---
@@ -888,3 +890,20 @@ body:             |
     RET_ReallyLR implicit $x0
 
 ...
+
+---
+name:            test_restricted_tail_call
+legalized:       true
+tracksRegLiveness: true
+body: |
+  bb.0:
+    liveins: $x16, $x17
+    ; CHECK-LABEL: name: test_restricted_tail_call
+    ; CHECK: liveins: $x16, $x17
+    ; CHECK: [[COPY:%[0-9]+]]:gpr(s64) = COPY $x16
+    ; CHECK: [[COPY1:%[0-9]+]]:gpr(s64) = COPY $x17
+    ; CHECK: RET_ReallyLR
+    %0:_(s64) = COPY $x16
+    %1:_(s64) = COPY $x17
+    RET_ReallyLR
+...