[llvm-branch-commits] [llvm] 068a23f - [LoopDistribute] Add tests with uncomputable BTCs.

[Florian Hahn via llvm-branch-commits]

Author: Florian Hahn
Date: 2021-01-01T13:57:03Z
New Revision: 068a23f05f94ae5573c885e832b3e6e95d298ac0

URL: https://github.com/llvm/llvm-project/commit/068a23f05f94ae5573c885e832b3e6e95d298ac0
DIFF: https://github.com/llvm/llvm-project/commit/068a23f05f94ae5573c885e832b3e6e95d298ac0.diff

LOG: [LoopDistribute] Add tests with uncomputable BTCs.

Added: 
    llvm/test/Transforms/LoopDistribute/uncomputable-backedge-taken-count.ll

Modified: 
    

Removed: 
    


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diff  --git a/llvm/test/Transforms/LoopDistribute/uncomputable-backedge-taken-count.ll b/llvm/test/Transforms/LoopDistribute/uncomputable-backedge-taken-count.ll
new file mode 100644
index 000000000000..20b47df15b2d
--- /dev/null
+++ b/llvm/test/Transforms/LoopDistribute/uncomputable-backedge-taken-count.ll
@@ -0,0 +1,86 @@
+; RUN: opt -basic-aa -loop-distribute -enable-loop-distribute -verify-loop-info -verify-dom-info -S \
+; RUN:   < %s | FileCheck %s
+
+target datalayout = "e-m:o-i32:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.10.0"
+
+; NOTE: The tests below use infinite loops to force unknown backedge-taken counts.
+; Making the exit condition depend on a load would break current loop-distribute,
+; because it requires all accesses to end up in either of the loops, but not both.
+
+; TODO
+; Can distribute with unknown backedge-taken count, because no runtime checks are
+; required.
+define void @unknown_btc_distribute_no_checks_needed(i32* noalias %a,
+               i32* noalias %c,
+               i32* noalias %d) {
+; CHECK-LABEL: @unknown_btc_distribute_no_checks_needed(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label %for.body
+;
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %ind = phi i32 [ 0, %entry ], [ %add, %for.body ]
+
+  %arrayidxA = getelementptr inbounds i32, i32* %a, i32 %ind
+  %loadA = load i32, i32* %arrayidxA, align 4
+
+  %mulA = mul i32 %loadA, 10
+
+  %add = add nuw nsw i32 %ind, 1
+  %arrayidxA_plus_4 = getelementptr inbounds i32, i32* %a, i32 %add
+  store i32 %mulA, i32* %arrayidxA_plus_4, align 4
+
+  %arrayidxD = getelementptr inbounds i32, i32* %d, i32 %ind
+  %loadD = load i32, i32* %arrayidxD, align 4
+
+  %mulC = mul i32 %loadD, 20
+
+  %arrayidxC = getelementptr inbounds i32, i32* %c, i32 %ind
+  store i32 %mulC, i32* %arrayidxC, align 4
+
+  br i1 false, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body
+  ret void
+}
+
+; Cannot distribute with unknown backedge-taken count, because runtime checks for
+; induction wrapping are required.
+define void @unknown_btc_do_not_distribute_wrapping_checks(i32* noalias %a,
+               i32* noalias %c,
+               i32* noalias %d) {
+; CHECK-LABEL: @unknown_btc_do_not_distribute_wrapping_checks(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label %for.body
+;
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %ind = phi i32 [ 0, %entry ], [ %add, %for.body ]
+
+  %arrayidxA = getelementptr inbounds i32, i32* %a, i32 %ind
+  %loadA = load i32, i32* %arrayidxA, align 4
+
+  %mulA = mul i32 %loadA, 10
+
+  %add = add i32 %ind, 1
+  %arrayidxA_plus_4 = getelementptr inbounds i32, i32* %a, i32 %add
+  store i32 %mulA, i32* %arrayidxA_plus_4, align 4
+
+  %arrayidxD = getelementptr inbounds i32, i32* %d, i32 %ind
+  %loadD = load i32, i32* %arrayidxD, align 4
+
+  %mulC = mul i32 %loadD, 20
+
+  %arrayidxC = getelementptr inbounds i32, i32* %c, i32 %ind
+  store i32 %mulC, i32* %arrayidxC, align 4
+
+  br i1 false, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body
+  ret void
+}