[clang] [llvm] [BPF] Add load-acquire and store-release instructions under -mcpu=v4 (PR #108636)

[Peilin Ye via cfe-commits]

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@@ -0,0 +1,106 @@
+; RUN: llc < %s -march=bpfel -mcpu=v4 -verify-machineinstrs -show-mc-encoding \
+; RUN:   | FileCheck -check-prefixes=CHECK-LE %s
+; RUN: llc < %s -march=bpfeb -mcpu=v4 -verify-machineinstrs -show-mc-encoding \
+; RUN:   | FileCheck -check-prefixes=CHECK-BE %s
+
+; Source:
+;   char load_acquire_i8(char *p) {
+;     return __atomic_load_n(p, __ATOMIC_ACQUIRE);
+;   }
+;   short load_acquire_i16(short *p) {
+;     return __atomic_load_n(p, __ATOMIC_ACQUIRE);
+;   }
+;   int load_acquire_i32(int *p) {
+;     return __atomic_load_n(p, __ATOMIC_ACQUIRE);
+;   }
+;   long load_acquire_i64(long *p) {
+;     return __atomic_load_n(p, __ATOMIC_ACQUIRE);
+;   }
+;   void store_release_i8(char *p, char v) {
+;     __atomic_store_n(p, v, __ATOMIC_RELEASE);
+;   }
+;   void store_release_i16(short *p, short v) {
+;     __atomic_store_n(p, v, __ATOMIC_RELEASE);
+;   }
+;   void store_release_i32(int *p, int v) {
+;     __atomic_store_n(p, v, __ATOMIC_RELEASE);
+;   }
+;   void store_release_i64(long *p, long v) {
+;     __atomic_store_n(p, v, __ATOMIC_RELEASE);
+;   }
+
+; CHECK-LABEL: load_acquire_i8
+; CHECK-LE: w0 = load_acquire((u8 *)(r1 + 0)) # encoding: [0xd3,0x10,0x00,0x00,0x10,0x00,0x00,0x00]
+; CHECK-BE: w0 = load_acquire((u8 *)(r1 + 0)) # encoding: [0xd3,0x01,0x00,0x00,0x00,0x00,0x00,0x10]
+define dso_local i8 @load_acquire_i8(ptr nocapture noundef readonly %p) local_unnamed_addr {
+entry:
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peilin-ye wrote:

Got it, thanks for reviewing this!  I'll run `acquire-release.ll` through `update_llc_test_checks.py`.

https://github.com/llvm/llvm-project/pull/108636