[IPSCCP] Use input operand instead of OriginalOp for ssa_copy.

OriginalOp of a Predicate refers to the original IR value,
before renaming. While solving in IPSCCP, we have to use
the operand of the ssa_copy instead, to avoid missing
updates for nested conditions on the same IR value.

Fixes PR39772.

llvm-svn: 347524

1 files changed, 50 insertions, 0 deletions

diff --git a/llvm/test/Transforms/SCCP/ipsccp-ssa-copy-nested-conds.ll b/llvm/test/Transforms/SCCP/ipsccp-ssa-copy-nested-conds.ll
new file mode 100644
index 00000000000..82f7db801bd
--- /dev/null
+++ b/llvm/test/Transforms/SCCP/ipsccp-ssa-copy-nested-conds.ll
@@ -0,0 +1,50 @@
+; RUN: opt < %s -ipsccp -S | FileCheck %s
+; RUN: opt < %s -passes=ipsccp -S | FileCheck %s
+
+; Test for PR39772
+; CHECK-LABEL: cleanup:
+; CHECK-NEXT:   %retval.0 = phi i32 [ 0, %if.then ], [ %add, %if.then7 ], [ %add8, %if.else ]
+
+
+%struct.Node = type { %struct.Node*, %struct.Node*, i32 }
+
+define i32 @check(%struct.Node* %node) {
+entry:
+  %cmp = icmp eq %struct.Node* %node, null
+  br i1 %cmp, label %if.then, label %if.end
+
+if.then:                                          ; preds = %entry
+  br label %cleanup
+
+if.end:                                           ; preds = %entry
+  %left = getelementptr inbounds %struct.Node, %struct.Node* %node, i32 0, i32 0
+  %0 = load %struct.Node*, %struct.Node** %left
+  %call = call i32 @check(%struct.Node* %0)
+  %right = getelementptr inbounds %struct.Node, %struct.Node* %node, i32 0, i32 1
+  %1 = load %struct.Node*, %struct.Node** %right
+  %call1 = call i32 @check(%struct.Node* %1)
+  %2 = load %struct.Node*, %struct.Node** %right
+  %height = getelementptr inbounds %struct.Node, %struct.Node* %2, i32 0, i32 2
+  %3 = load i32, i32* %height
+  %cmp3 = icmp ne i32 %3, %call1
+  br i1 %cmp3, label %if.then4, label %if.end5
+
+if.then4:                                         ; preds = %if.end
+  unreachable
+
+if.end5:                                          ; preds = %if.end
+  %cmp6 = icmp sgt i32 %call, %call1
+  br i1 %cmp6, label %if.then7, label %if.else
+
+if.then7:                                         ; preds = %if.end5
+  %add = add nsw i32 %call, 1
+  br label %cleanup
+
+if.else:                                          ; preds = %if.end5
+  %add8 = add nsw i32 %call1, 1
+  br label %cleanup
+
+cleanup:                                          ; preds = %if.else, %if.then7, %if.then
+  %retval.0 = phi i32 [ 0, %if.then ], [ %add, %if.then7 ], [ %add8, %if.else ]
+  ret i32 %retval.0
+}