[PATCH] D117184: Fix failing assertion in SimplifyCFG.cpp as icmp gep fold to constant expression [NFC]

[praveen velliengiri via Phabricator via llvm-commits]

pvellien updated this revision to Diff 400493.
pvellien added a comment.

@nikic Thanks a lot for the detailed description to reduce the test-case, it greatly helped me. 
Updated the patch with test-cases.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D117184/new/

https://reviews.llvm.org/D117184

Files:
  llvm/lib/Transforms/Utils/SimplifyCFG.cpp
  llvm/test/Transforms/SimplifyCFG/X86/switch-to-lookup-globals.ll


Index: llvm/test/Transforms/SimplifyCFG/X86/switch-to-lookup-globals.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/SimplifyCFG/X86/switch-to-lookup-globals.ll
@@ -0,0 +1,32 @@
+; RUN: opt -S -passes="simplifycfg<switch-to-lookup>" < %s | FileCheck %s
+
+target triple = "x86_64-unknown-linux-gnu"
+
+%struct.ham = type <{ i32, i32, i32, i8, i8, [2 x i8] }>
+
+ at global = external constant [75 x { i32, i32, i32, i8, i8 }]
+
+; CHECK:  [[SWITCH_GEP:%.*]] = getelementptr inbounds [3 x %struct.ham*], [3 x %struct.ham*]* @switch.table.zot, i32 0, i32 %arg
+; CHECK-NEXT: [[SWITCH_LOAD:%.*]] = load %struct.ham*, %struct.ham** [[SWITCH_GEP]], align 8
+
+define i1 @zot(i32 %arg) {
+bb:
+  %tmp = icmp eq i32 %arg, 1
+  br i1 %tmp, label %bb6, label %bb1
+
+bb1:                                              ; preds = %bb
+  %tmp2 = icmp eq i32 %arg, 2
+  br i1 %tmp2, label %bb6, label %bb3
+
+bb3:                                              ; preds = %bb1
+  %tmp4 = icmp eq i32 %arg, 0
+  br i1 %tmp4, label %bb6, label %bb5
+
+bb5:                                              ; preds = %bb3
+  br label %bb6
+
+bb6:                                              ; preds = %bb5, %bb3, %bb1, %bb
+  %tmp7 = phi %struct.ham* [ null, %bb5 ], [ bitcast (i32* getelementptr inbounds ([75 x { i32, i32, i32, i8, i8 }], [75 x { i32, i32, i32, i8, i8 }]* @global, i64 0, i64 6, i32 0) to %struct.ham*), %bb ], [ null, %bb1 ], [ null, %bb3 ]
+  %tmp8 = icmp eq %struct.ham* %tmp7, bitcast (i32* getelementptr inbounds ([75 x { i32, i32, i32, i8, i8 }], [75 x { i32, i32, i32, i8, i8 }]* @global, i64 1, i64 0, i32 0) to %struct.ham*)
+  ret i1 %tmp8
+}
Index: llvm/lib/Transforms/Utils/SimplifyCFG.cpp
===================================================================
--- llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -5807,8 +5807,6 @@
                                                 ValuePair.second, CmpOp1, true);
     if (!CaseConst || CaseConst == DefaultConst || isa<UndefValue>(CaseConst))
       return;
-    assert((CaseConst == TrueConst || CaseConst == FalseConst) &&
-           "Expect true or false as compare result.");
   }
 
   // Check if the branch instruction dominates the phi node. It's a simple


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