[AArch64] Support reserving x1-7 registers.

Summary:
Reserving registers x1-7 is used to support CONFIG_ARM64_LSE_ATOMICS in Linux kernel. This change adds support for reserving registers x1 through x7.

Reviewers: javed.absar, phosek, srhines, nickdesaulniers, efriedma

Reviewed By: nickdesaulniers, efriedma

Subscribers: niravd, jfb, manojgupta, nickdesaulniers, jyknight, efriedma, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D48580

llvm-svn: 341706

2 files changed, 76 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/AArch64/arm64-platform-reg.ll b/llvm/test/CodeGen/AArch64/arm64-platform-reg.ll
index 899759624c2..73fe36d7611 100644
--- a/llvm/test/CodeGen/AArch64/arm64-platform-reg.ll
+++ b/llvm/test/CodeGen/AArch64/arm64-platform-reg.ll
@@ -7,6 +7,49 @@
 ; RUN: llc -mtriple=aarch64-fuchsia -o - %s | FileCheck %s --check-prefix=CHECK-RESERVE --check-prefix=CHECK-RESERVE-X18
 ; RUN: llc -mtriple=aarch64-windows -o - %s | FileCheck %s --check-prefix=CHECK-RESERVE --check-prefix=CHECK-RESERVE-X18
 
+; Test reserve-x# options individually.
+; RUN: llc -mtriple=arm64-linux-gnu -mattr=+reserve-x1 -o - %s | FileCheck %s --check-prefixes=CHECK-RESERVE,CHECK-RESERVE-X1
+; RUN: llc -mtriple=arm64-linux-gnu -mattr=+reserve-x2 -o - %s | FileCheck %s --check-prefixes=CHECK-RESERVE,CHECK-RESERVE-X2
+; RUN: llc -mtriple=arm64-linux-gnu -mattr=+reserve-x3 -o - %s | FileCheck %s --check-prefixes=CHECK-RESERVE,CHECK-RESERVE-X3
+; RUN: llc -mtriple=arm64-linux-gnu -mattr=+reserve-x4 -o - %s | FileCheck %s --check-prefixes=CHECK-RESERVE,CHECK-RESERVE-X4
+; RUN: llc -mtriple=arm64-linux-gnu -mattr=+reserve-x5 -o - %s | FileCheck %s --check-prefixes=CHECK-RESERVE,CHECK-RESERVE-X5
+; RUN: llc -mtriple=arm64-linux-gnu -mattr=+reserve-x6 -o - %s | FileCheck %s --check-prefixes=CHECK-RESERVE,CHECK-RESERVE-X6
+; RUN: llc -mtriple=arm64-linux-gnu -mattr=+reserve-x7 -o - %s | FileCheck %s --check-prefixes=CHECK-RESERVE,CHECK-RESERVE-X7
+
+; Test multiple of reserve-x# options together.
+; RUN: llc -mtriple=arm64-linux-gnu \
+; RUN: -mattr=+reserve-x1 \
+; RUN: -mattr=+reserve-x2 \
+; RUN: -mattr=+reserve-x18 \
+; RUN: -o - %s | FileCheck %s \
+; RUN: --check-prefix=CHECK-RESERVE \
+; RUN: --check-prefix=CHECK-RESERVE-X1 \
+; RUN: --check-prefix=CHECK-RESERVE-X2 \
+; RUN: --check-prefix=CHECK-RESERVE-X18
+
+; Test all reserve-x# options together.
+; RUN: llc -mtriple=arm64-linux-gnu \
+; RUN: -mattr=+reserve-x1 \
+; RUN: -mattr=+reserve-x2 \
+; RUN: -mattr=+reserve-x3 \
+; RUN: -mattr=+reserve-x4 \
+; RUN: -mattr=+reserve-x5 \
+; RUN: -mattr=+reserve-x6 \
+; RUN: -mattr=+reserve-x7 \
+; RUN: -mattr=+reserve-x18 \
+; RUN: -mattr=+reserve-x20 \
+; RUN: -o - %s | FileCheck %s \
+; RUN: --check-prefix=CHECK-RESERVE \
+; RUN: --check-prefix=CHECK-RESERVE-X1 \
+; RUN: --check-prefix=CHECK-RESERVE-X2 \
+; RUN: --check-prefix=CHECK-RESERVE-X3 \
+; RUN: --check-prefix=CHECK-RESERVE-X4 \
+; RUN: --check-prefix=CHECK-RESERVE-X5 \
+; RUN: --check-prefix=CHECK-RESERVE-X6 \
+; RUN: --check-prefix=CHECK-RESERVE-X7 \
+; RUN: --check-prefix=CHECK-RESERVE-X18 \
+; RUN: --check-prefix=CHECK-RESERVE-X20
+
 ; x18 is reserved as a platform register on Darwin but not on other
 ; systems. Create loads of register pressure and make sure this is respected.
 
@@ -23,10 +66,24 @@ define void @keep_live() {
 ; CHECK: str x18
 
 ; CHECK-RESERVE-NOT: ldr fp
+; CHECK-RESERVE-X1-NOT: ldr x1,
+; CHECK-RESERVE-X2-NOT: ldr x2,
+; CHECK-RESERVE-X3-NOT: ldr x3,
+; CHECK-RESERVE-X4-NOT: ldr x4,
+; CHECK-RESERVE-X5-NOT: ldr x5,
+; CHECK-RESERVE-X6-NOT: ldr x6,
+; CHECK-RESERVE-X7-NOT: ldr x7,
 ; CHECK-RESERVE-X18-NOT: ldr x18
 ; CHECK-RESERVE-X20-NOT: ldr x20
 ; CHECK-RESERVE: Spill
 ; CHECK-RESERVE-NOT: ldr fp
+; CHECK-RESERVE-X1-NOT: ldr x1,
+; CHECK-RESERVE-X2-NOT: ldr x2,
+; CHECK-RESERVE-X3-NOT: ldr x3,
+; CHECK-RESERVE-X4-NOT: ldr x4,
+; CHECK-RESERVE-X5-NOT: ldr x5,
+; CHECK-RESERVE-X6-NOT: ldr x6,
+; CHECK-RESERVE-X7-NOT: ldr x7,
 ; CHECK-RESERVE-X18-NOT: ldr x18
 ; CHECK-RESERVE-X20-NOT: ldr x20
 ; CHECK-RESERVE: ret
diff --git a/llvm/test/CodeGen/AArch64/arm64-reserved-arg-reg-call-error.ll b/llvm/test/CodeGen/AArch64/arm64-reserved-arg-reg-call-error.ll
new file mode 100644
index 00000000000..b98b11e180e
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/arm64-reserved-arg-reg-call-error.ll
@@ -0,0 +1,19 @@
+; RUN: not llc < %s -mtriple=arm64-linux-gnu -mattr=+reserve-x1 2>&1 | FileCheck %s
+; RUN: not llc < %s -mtriple=arm64-linux-gnu -mattr=+reserve-x1 -fast-isel 2>&1 | FileCheck %s
+; RUN: not llc < %s -mtriple=arm64-linux-gnu -mattr=+reserve-x1 -global-isel 2>&1 | FileCheck %s
+
+; CHECK: error:
+; CHECK-SAME: AArch64 doesn't support function calls if any of the argument registers is reserved.
+define void @call_function() {
+  call void @foo()
+  ret void
+}
+declare void @foo()
+
+; CHECK: error:
+; CHECK-SAME: AArch64 doesn't support function calls if any of the argument registers is reserved.
+define void @call_memcpy(i8* %out, i8* %in) {
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %out, i8* %in, i64 800, i1 false)
+  ret void
+}
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8*, i8*, i64, i1)