[llvm] [ARM] Add test for thumb2-reduce-size NFC (PR #112333)

[David Green via llvm-commits]

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@@ -0,0 +1,67 @@
+# RUN: llc -run-pass=thumb2-reduce-size %s -o - | FileCheck %s
+
+--- |
+  target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
+  target triple = "thumbv8m.main-arm-none-eabi"
+
+  ; Function Attrs: norecurse nounwind readnone
+  define i32 @test(i32 %x, i32 %y) local_unnamed_addr #0 {
+  entry:
+    %cmp6 = icmp sgt i32 %y, 0
+    br i1 %cmp6, label %for.body.preheader, label %for.cond.cleanup
+
+  for.body.preheader:                               ; preds = %entry
+    br label %for.body
+
+  for.cond.cleanup:                                 ; preds = %for.body, %entry
+    %sum.0.lcssa = phi i32 [ 1, %entry ], [ %mul, %for.body ]
+    ret i32 %sum.0.lcssa
+
+  for.body:                                         ; preds = %for.body, %for.body.preheader
+    %lsr.iv1 = phi i32 [ %lsr.iv.next2, %for.body ], [ %x, %for.body.preheader ]
+    %lsr.iv = phi i32 [ %lsr.iv.next, %for.body ], [ %y, %for.body.preheader ]
+    %sum.07 = phi i32 [ %mul, %for.body ], [ 1, %for.body.preheader ]
+    %mul = mul nsw i32 %lsr.iv1, %sum.07
+    %lsr.iv.next = add i32 %lsr.iv, -1
+    %lsr.iv.next2 = add i32 %lsr.iv1, 1
+    %exitcond = icmp eq i32 %lsr.iv.next, 0
+    br i1 %exitcond, label %for.cond.cleanup, label %for.body
+  }
+
+  attributes #0 = { norecurse nounwind readnone "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="cortex-m33" "target-features"="-d32,+dsp,+fp-armv8,-fp64,+hwdiv,+strict-align,+thumb-mode,-crc,-dotprod,-hwdiv-arm,-ras" "unsafe-fp-math"="false" "use-soft-float"="false" }
----------------
davemgreen wrote:

A lot of this can be removed, to help simplify the test. It might be possible to remove the entire ir section and have two run lines that run with/without -mcpu=cortex-m33. That way it can test that both versions with the muls and with the mul are working OK.

https://github.com/llvm/llvm-project/pull/112333