[PATCH] D49049: [LSR] If no Use is interesting, early return.

[Tim Shen via Phabricator via llvm-commits]

timshen updated this revision to Diff 155524.
timshen marked an inline comment as done.
timshen added a comment.

TIL -metarenamer.


https://reviews.llvm.org/D49049

Files:
  llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
  llvm/test/CodeGen/X86/lsr-crash-empty-uses.ll


Index: llvm/test/CodeGen/X86/lsr-crash-empty-uses.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/X86/lsr-crash-empty-uses.ll
@@ -0,0 +1,41 @@
+; RUN: llc --start-before loop-reduce --stop-after loop-reduce %s -o - | FileCheck %s
+target datalayout = "e-m:e-p:32:32-i64:64-n32-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @hoge() {
+bb:
+  %tmp = sext i32 undef to i64
+  %tmp3 = sub nsw i64 0, %tmp
+  br label %bb4
+
+bb4:                                              ; preds = %bb20, %bb
+  %tmp5 = getelementptr inbounds double, double* undef, i64 undef
+  %tmp6 = getelementptr inbounds double, double* %tmp5, i64 %tmp3
+  br label %bb7
+
+bb7:                                              ; preds = %bb7, %bb4
+  %tmp8 = phi double* [ %tmp10, %bb7 ], [ %tmp6, %bb4 ]
+  %tmp9 = load double, double* %tmp8
+  %tmp10 = getelementptr inbounds double, double* %tmp8, i64 1
+  br i1 true, label %bb11, label %bb7
+
+bb11:                                             ; preds = %bb7
+  br i1 undef, label %bb20, label %bb12
+
+bb12:                                             ; preds = %bb11
+  br label %bb13
+
+bb13:                                             ; preds = %bb13, %bb12
+  %tmp14 = phi double* [ %tmp18, %bb13 ], [ %tmp10, %bb12 ]
+  %tmp15 = load double, double* %tmp14, align 8
+  %tmp16 = getelementptr inbounds double, double* %tmp14, i64 1
+  %tmp17 = load double, double* %tmp16, align 8
+  %tmp18 = getelementptr inbounds double, double* %tmp14, i64 8
+  br i1 true, label %bb19, label %bb13
+
+bb19:                                             ; preds = %bb13
+  br label %bb20
+
+bb20:                                             ; preds = %bb19, %bb11
+  br label %bb4
+}
Index: llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -5400,7 +5400,9 @@
   CollectFixupsAndInitialFormulae();
   CollectLoopInvariantFixupsAndFormulae();
 
-  assert(!Uses.empty() && "IVUsers reported at least one use");
+  if (Uses.empty())
+    return;
+
   LLVM_DEBUG(dbgs() << "LSR found " << Uses.size() << " uses:\n";
              print_uses(dbgs()));
 


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