[AMDGPU] Lower null pointers in static variable initializer

    For amdgcn target Clang generates addrspacecast to represent null pointers in private and local address spaces.

    In LLVM codegen, the static variable initializer is lowered by virtual function AsmPrinter::lowerConstant which is target generic. Since addrspacecast is target specific, AsmPrinter::lowerConst

    This patch overrides AsmPrinter::lowerConstant with AMDGPUAsmPrinter::lowerConstant, which is able to lower the target-specific addrspacecast in the null pointer representation so that -1 is co

    Differential Revision: https://reviews.llvm.org/D29284

llvm-svn: 294265

1 files changed, 113 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/AMDGPU/nullptr.ll b/llvm/test/CodeGen/AMDGPU/nullptr.ll
new file mode 100644
index 00000000000..b4bdf71fa90
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/nullptr.ll
@@ -0,0 +1,113 @@
+;RUN: llc < %s -march=amdgcn -verify-machineinstrs | FileCheck %s
+
+%struct.S = type { i32*, i32 addrspace(1)*, i32 addrspace(2)*, i32 addrspace(3)*, i32 addrspace(4)*, i32 addrspace(5)*}
+
+; CHECK-LABEL: nullptr_priv:
+; CHECK-NEXT: .long -1
+@nullptr_priv = global i32* addrspacecast (i32 addrspace(4)* null to i32*)
+
+; CHECK-LABEL: nullptr_glob:
+; CHECK-NEXT: .quad 0
+@nullptr_glob = global i32 addrspace(1)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(1)*)
+
+; CHECK-LABEL: nullptr_const:
+; CHECK-NEXT: .quad 0
+@nullptr_const = global i32 addrspace(2)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(2)*)
+
+; CHECK-LABEL: nullptr_local:
+; CHECK-NEXT: .long -1
+@nullptr_local = global i32 addrspace(3)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(3)*)
+
+; CHECK-LABEL: nullptr_region:
+; CHECK-NEXT: .long -1
+@nullptr_region = global i32 addrspace(5)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(5)*)
+
+; CHECK-LABEL: nullptr6:
+; CHECK-NEXT: .long 0
+@nullptr6 = global i32 addrspace(6)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(6)*)
+
+; CHECK-LABEL: nullptr7:
+; CHECK-NEXT: .long 0
+@nullptr7 = global i32 addrspace(7)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(7)*)
+
+; CHECK-LABEL: nullptr8:
+; CHECK-NEXT: .long 0
+@nullptr8 = global i32 addrspace(8)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(8)*)
+
+; CHECK-LABEL: nullptr9:
+; CHECK-NEXT: .long 0
+@nullptr9 = global i32 addrspace(9)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(9)*)
+
+; CHECK-LABEL: nullptr10:
+; CHECK-NEXT: .long 0
+@nullptr10 = global i32 addrspace(10)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(10)*)
+
+; CHECK-LABEL: nullptr11:
+; CHECK-NEXT: .long 0
+@nullptr11 = global i32 addrspace(11)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(11)*)
+
+; CHECK-LABEL: nullptr12:
+; CHECK-NEXT: .long 0
+@nullptr12 = global i32 addrspace(12)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(12)*)
+
+; CHECK-LABEL: nullptr13:
+; CHECK-NEXT: .long 0
+@nullptr13 = global i32 addrspace(13)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(13)*)
+
+; CHECK-LABEL: nullptr14:
+; CHECK-NEXT: .long 0
+@nullptr14 = global i32 addrspace(14)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(14)*)
+
+; CHECK-LABEL: nullptr15:
+; CHECK-NEXT: .long 0
+@nullptr15 = global i32 addrspace(15)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(15)*)
+
+; CHECK-LABEL: nullptr16:
+; CHECK-NEXT: .long 0
+@nullptr16 = global i32 addrspace(16)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(16)*)
+
+; CHECK-LABEL: nullptr17:
+; CHECK-NEXT: .long 0
+@nullptr17 = global i32 addrspace(17)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(17)*)
+
+; CHECK-LABEL: nullptr18:
+; CHECK-NEXT: .long 0
+@nullptr18 = global i32 addrspace(18)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(18)*)
+
+; CHECK-LABEL: nullptr19:
+; CHECK-NEXT: .long 0
+@nullptr19 = global i32 addrspace(19)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(19)*)
+
+; CHECK-LABEL: nullptr20:
+; CHECK-NEXT: .long 0
+@nullptr20 = global i32 addrspace(20)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(20)*)
+
+; CHECK-LABEL: nullptr21:
+; CHECK-NEXT: .long 0
+@nullptr21 = global i32 addrspace(21)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(21)*)
+
+; CHECK-LABEL: nullptr22:
+; CHECK-NEXT: .long 0
+@nullptr22 = global i32 addrspace(22)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(22)*)
+
+; CHECK-LABEL: nullptr23:
+; CHECK-NEXT: .long 0
+@nullptr23 = global i32 addrspace(23)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(23)*)
+
+; CHECK-LABEL: structWithPointers:
+; CHECK-NEXT: .long -1
+; CHECK-NEXT: .zero 4
+; CHECK-NEXT: .quad 0
+; CHECK-NEXT: .quad 0
+; CHECK-NEXT: .long -1
+; CHECK-NEXT: .zero 4
+; CHECK-NEXT: .quad 0
+; CHECK-NEXT: .long -1
+; CHECK-NEXT: .zero 4
+@structWithPointers = addrspace(1) global %struct.S {
+  i32* addrspacecast (i32 addrspace(4)* null to i32*),
+  i32 addrspace(1)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(1)*),
+  i32 addrspace(2)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(2)*),
+  i32 addrspace(3)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(3)*),
+  i32 addrspace(4)* null,
+  i32 addrspace(5)* addrspacecast (i32 addrspace(4)* null to i32 addrspace(5)*)}, align 4