From 04f826c0625a9701dd941fa0fb5db110f5971421 Mon Sep 17 00:00:00 2001
From: Saleem Abdulrasool <compnerd@compnerd.org>
Date: Fri, 25 Apr 2014 17:24:24 +0000
Subject: [PATCH] ARM: provide a new generic hint intrinsic

Introduce the llvm.arm.hint(i32) intrinsic that can be used to inject hints into
the instruction stream. This is particularly useful for generating IR from a
compiler where the user may inject an intrinsic (e.g. __yield). These are then
pattern substituted into the correct instruction which already existed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207242 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/IR/IntrinsicsARM.td |  1 +
 lib/Target/ARM/ARMInstrInfo.td   |  3 +-
 lib/Target/ARM/ARMInstrThumb.td  |  3 +-
 lib/Target/ARM/ARMInstrThumb2.td |  3 +-
 test/CodeGen/ARM/hints.ll        | 69 ++++++++++++++++++++++++++++++++
 5 files changed, 76 insertions(+), 3 deletions(-)
 create mode 100644 test/CodeGen/ARM/hints.ll

diff --git a/include/llvm/IR/IntrinsicsARM.td b/include/llvm/IR/IntrinsicsARM.td
index 482f98ef895..d50f17acdc0 100644
--- a/include/llvm/IR/IntrinsicsARM.td
+++ b/include/llvm/IR/IntrinsicsARM.td
@@ -123,6 +123,7 @@ def int_arm_crc32cw : Intrinsic<[llvm_i32_ty], [llvm_i32_ty, llvm_i32_ty],
 //===----------------------------------------------------------------------===//
 // HINT
 def int_arm_sevl : Intrinsic<[], []>;
+def int_arm_hint : Intrinsic<[], [llvm_i32_ty]>;
 
 //===----------------------------------------------------------------------===//
 // Advanced SIMD (NEON)
diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index c27ffeed890..ad88bf0ba6b 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -1827,7 +1827,8 @@ PseudoInst<(outs), (ins i32imm:$amt, pred:$p), NoItinerary,
 }
 
 def HINT : AI<(outs), (ins imm0_239:$imm), MiscFrm, NoItinerary,
-              "hint", "\t$imm", []>, Requires<[IsARM, HasV6]> {
+              "hint", "\t$imm", [(int_arm_hint imm0_239:$imm)]>,
+           Requires<[IsARM, HasV6]> {
   bits<8> imm;
   let Inst{27-8} = 0b00110010000011110000;
   let Inst{7-0} = imm;
diff --git a/lib/Target/ARM/ARMInstrThumb.td b/lib/Target/ARM/ARMInstrThumb.td
index 754295f93fd..ed72d24a811 100644
--- a/lib/Target/ARM/ARMInstrThumb.td
+++ b/lib/Target/ARM/ARMInstrThumb.td
@@ -269,7 +269,8 @@ class T1SystemEncoding<bits<8> opc>
   let Inst{7-0} = opc;
 }
 
-def tHINT : T1pI<(outs), (ins imm0_15:$imm), NoItinerary, "hint", "\t$imm", []>,
+def tHINT : T1pI<(outs), (ins imm0_15:$imm), NoItinerary, "hint", "\t$imm",
+                 [(int_arm_hint imm0_15:$imm)]>,
             T1SystemEncoding<0x00>,
             Requires<[IsThumb, HasV6M]> {
   bits<4> imm;
diff --git a/lib/Target/ARM/ARMInstrThumb2.td b/lib/Target/ARM/ARMInstrThumb2.td
index c30bf697623..1e4aa0d6abe 100644
--- a/lib/Target/ARM/ARMInstrThumb2.td
+++ b/lib/Target/ARM/ARMInstrThumb2.td
@@ -3671,7 +3671,8 @@ def : t2InstAlias<"cps.w $mode", (t2CPS1p imm0_31:$mode), 0>;
 
 // A6.3.4 Branches and miscellaneous control
 // Table A6-14 Change Processor State, and hint instructions
-def t2HINT : T2I<(outs), (ins imm0_239:$imm), NoItinerary, "hint", ".w\t$imm",[]> {
+def t2HINT : T2I<(outs), (ins imm0_239:$imm), NoItinerary, "hint", ".w\t$imm",
+                  [(int_arm_hint imm0_239:$imm)]> {
   bits<8> imm;
   let Inst{31-3} = 0b11110011101011111000000000000;
   let Inst{7-0} = imm;
diff --git a/test/CodeGen/ARM/hints.ll b/test/CodeGen/ARM/hints.ll
new file mode 100644
index 00000000000..18abbbecaaf
--- /dev/null
+++ b/test/CodeGen/ARM/hints.ll
@@ -0,0 +1,69 @@
+; RUN: llc -mtriple armv7-eabi -o - %s | FileCheck %s
+; RUN: llc -mtriple thumbv6m-eabi -o - %s | FileCheck %s
+; RUN: llc -mtriple thumbv7-eabi -o - %s | FileCheck %s
+
+declare void @llvm.arm.hint(i32) nounwind
+
+define void @hint_nop() {
+entry:
+  tail call void @llvm.arm.hint(i32 0) nounwind
+  ret void
+}
+
+; CHECK-LABEL: hint_nop
+; CHECK: nop
+
+define void @hint_yield() {
+entry:
+  tail call void @llvm.arm.hint(i32 1) nounwind
+  ret void
+}
+
+; CHECK-LABEL: hint_yield
+; CHECK: yield
+
+define void @hint_wfe() {
+entry:
+  tail call void @llvm.arm.hint(i32 2) nounwind
+  ret void
+}
+
+; CHECK-LABEL: hint_wfe
+; CHECK: wfe
+
+define void @hint_wfi() {
+entry:
+  tail call void @llvm.arm.hint(i32 3) nounwind
+  ret void
+}
+
+; CHECK-LABEL: hint_wfi
+; CHECK: wfi
+
+define void @hint_sev() {
+entry:
+  tail call void @llvm.arm.hint(i32 4) nounwind
+  ret void
+}
+
+; CHECK-LABEL: hint_sev
+; CHECK: sev
+
+define void @hint_sevl() {
+entry:
+  tail call void @llvm.arm.hint(i32 5) nounwind
+  ret void
+}
+
+; CHECK-LABEL: hint_sevl
+; CHECK: hint #5
+
+define void @hint_undefined() {
+entry:
+  tail call void @llvm.arm.hint(i32 8) nounwind
+  ret void
+}
+
+; CHECK-LABEL: hint_undefined
+; CHECK: hint #8
+