[PATCH] D99990: [NewGVN] Use performSymbolicEvaluation instead of createExpression.

[Florian Hahn via Phabricator via llvm-commits]

fhahn updated this revision to Diff 339991.
fhahn added a comment.

Rebased after landing 2b15262f89bc <https://reviews.llvm.org/rG2b15262f89bc0923361e1ed5b596a2d18d22afd9>


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D99990/new/

https://reviews.llvm.org/D99990

Files:
  llvm/lib/Transforms/Scalar/NewGVN.cpp
  llvm/test/Transforms/NewGVN/compare-condition-changes.ll


Index: llvm/test/Transforms/NewGVN/compare-condition-changes.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/NewGVN/compare-condition-changes.ll
@@ -0,0 +1,78 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -newgvn -S %s | FileCheck %s
+
+; Test cases to make sure the blocks are properly marked as executable, if the
+; state of the branch condition changes.
+
+define i1 @test1() {
+; CHECK-LABEL: @test1(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CALL:%.*]] = tail call i1 @foo()
+; CHECK-NEXT:    br i1 [[CALL]], label [[THEN:%.*]], label [[ELSE:%.*]]
+; CHECK:       then:
+; CHECK-NEXT:    ret i1 true
+; CHECK:       else:
+; CHECK-NEXT:    ret i1 false
+;
+entry:
+  %call = tail call i1 @foo()
+  br i1 %call, label %then, label %else
+
+then:
+  ret i1 true
+
+else:
+  ret i1 false
+}
+
+declare i1 @foo()
+
+; Make sure state changes are propagated across freeze to branches.
+define void @test2(i1 %c) {
+; CHECK-LABEL: @test2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP_HEADER:%.*]]
+; CHECK:       loop.header:
+; CHECK-NEXT:    [[P_0:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[LOOP_LATCH:%.*]] ]
+; CHECK-NEXT:    [[P_1:%.*]] = phi i32 [ 1, [[ENTRY]] ], [ [[P_2:%.*]], [[LOOP_LATCH]] ]
+; CHECK-NEXT:    br label [[LOOP_BB_1:%.*]]
+; CHECK:       loop.bb.1:
+; CHECK-NEXT:    [[INC]] = add nsw i32 [[P_0]], 1
+; CHECK-NEXT:    [[C_1:%.*]] = icmp slt i32 [[P_0]], 0
+; CHECK-NEXT:    [[C_1_FREEZE:%.*]] = freeze i1 [[C_1]]
+; CHECK-NEXT:    br i1 [[C_1_FREEZE]], label [[LOOP_BB_2:%.*]], label [[LOOP_LATCH]]
+; CHECK:       loop.bb.2:
+; CHECK-NEXT:    br label [[LOOP_LATCH]]
+; CHECK:       loop.latch:
+; CHECK-NEXT:    [[P_2]] = phi i32 [ 0, [[LOOP_BB_2]] ], [ [[P_1]], [[LOOP_BB_1]] ]
+; CHECK-NEXT:    [[C_2:%.*]] = icmp eq i32 [[P_2]], 123
+; CHECK-NEXT:    br i1 [[C_2]], label [[EXIT:%.*]], label [[LOOP_HEADER]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %p.0 = phi i32 [ 0, %entry ], [ %p.3, %loop.latch ]
+  %p.1 = phi i32 [ 1, %entry ], [ %p.2, %loop.latch ]
+  br label %loop.bb.1
+
+loop.bb.1:
+  %inc = add nsw i32 %p.0, 1
+  %c.1 = icmp slt i32 %p.0, 0
+  %c.1.freeze = freeze i1 %c.1
+  br i1 %c.1.freeze, label %loop.bb.2, label %loop.latch
+
+loop.bb.2:
+  br label %loop.latch
+
+loop.latch:
+  %p.2 = phi i32 [ 0, %loop.bb.2 ], [ %p.1, %loop.bb.1 ]
+  %p.3 = phi i32 [ %inc, %loop.bb.2 ], [ %inc, %loop.bb.1 ]
+  %c.2 = icmp eq i32 %p.2, 123
+  br i1 %c.2, label %exit, label %loop.header
+
+exit:
+  ret void
+}
Index: llvm/lib/Transforms/Scalar/NewGVN.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/NewGVN.cpp
+++ llvm/lib/Transforms/Scalar/NewGVN.cpp
@@ -2437,8 +2437,9 @@
     Value *CondEvaluated = findConditionEquivalence(Cond);
     if (!CondEvaluated) {
       if (auto *I = dyn_cast<Instruction>(Cond)) {
-        auto Res = createExpression(I);
-        if (const auto *CE = dyn_cast<ConstantExpression>(Res.Expr)) {
+        SmallPtrSet<Value *, 4> Visited;
+        auto Res = performSymbolicEvaluation(I, Visited);
+        if (const auto *CE = dyn_cast_or_null<ConstantExpression>(Res.Expr)) {
           CondEvaluated = CE->getConstantValue();
           addAdditionalUsers(Res, I);
         } else {


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D99990.339991.patch
Type: text/x-patch
Size: 3403 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20210423/7431f16f/attachment.bin>