[llvm] [AArch64][MachinePipeliner] Add pipeliner support for AArch64 (PR #79589)

[David Green via llvm-commits]

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@@ -0,0 +1,87 @@
+# RUN: llc --verify-machineinstrs -mtriple=aarch64 -o - %s -run-pass pipeliner -aarch64-enable-pipeliner -pipeliner-enable-copytophi=0 -debug-only=pipeliner 2>&1 | FileCheck %s
+
+# An acceptable loop by pipeliner TBB == LoopBB, FBB == ExitBB, Compare and branch
+# CHECK: Schedule Found? 1
+
+--- |
+  define dso_local void @func(ptr noalias nocapture noundef writeonly %a, ptr nocapture noundef readonly %b, i32 noundef %n) local_unnamed_addr #0 {
+  entry:
+    %or.cond = icmp ult i32 %n, 2
+    br i1 %or.cond, label %for.end, label %for.body.preheader
+  
+  for.body.preheader:                               ; preds = %entry
+    %i.07 = add i32 %n, -1
+    %0 = sext i32 %i.07 to i64
+    br label %for.body
+  
+  for.body:                                         ; preds = %for.body.preheader, %for.body
+    %indvars.iv = phi i64 [ %0, %for.body.preheader ], [ %indvars.iv.next, %for.body ]
+    %1 = shl nsw i64 %indvars.iv, 2
+    %scevgep = getelementptr i8, ptr %b, i64 %1
+    %2 = load float, ptr %scevgep, align 4, !tbaa !6
+    %add = fadd float %2, 1.000000e+00
+    %3 = shl nsw i64 %indvars.iv, 2
+    %scevgep11 = getelementptr i8, ptr %a, i64 %3
+    store float %add, ptr %scevgep11, align 4, !tbaa !6
+    %indvars.iv.next = add nsw i64 %indvars.iv, -1
+    %4 = add i64 %indvars.iv, -1
+    %5 = and i64 %4, 4294967295
+    %tobool.not = icmp eq i64 %5, 0
+    br i1 %tobool.not, label %for.end, label %for.body, !llvm.loop !10
+  
+  for.end:                                          ; preds = %for.body, %entry
+    ret void
+  }
+  
+  !6 = !{!7, !7, i64 0}
+  !7 = !{!"float", !8, i64 0}
+  !8 = !{!"omnipotent char", !9, i64 0}
+  !9 = !{!"Simple C/C++ TBAA"}
+  !10 = distinct !{!10, !11, !12}
+  !11 = !{!"llvm.loop.mustprogress"}
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davemgreen wrote:

You might be able to remove some of this metadata, if it is not important for the tests.

https://github.com/llvm/llvm-project/pull/79589