[PATCH] D107067: [FuncSpec] Ignore ConstantExpr when find possible constant

[Chuanqi Xu via Phabricator via llvm-commits]

ChuanqiXu created this revision.
ChuanqiXu added reviewers: SjoerdMeijer, fhahn.
Herald added subscribers: snehasish, ormris, hiraditya.
ChuanqiXu requested review of this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

Now the function specialization pass would crash for SPEC2017int rate.

The reason would be we didn't update the SCCPSolver after we replace the constant.
It would be fixed once we adopted D106426 <https://reviews.llvm.org/D106426>.

Since it looks like that D106426 <https://reviews.llvm.org/D106426> would take more time to check in, I think we could use this fix first.

Test Plan: check-all, SPEC2017 int rate


https://reviews.llvm.org/D107067

Files:
  llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
  llvm/test/Transforms/FunctionSpecialization/function-specialization-constant-expression.ll


Index: llvm/test/Transforms/FunctionSpecialization/function-specialization-constant-expression.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/FunctionSpecialization/function-specialization-constant-expression.ll
@@ -0,0 +1,57 @@
+; Test function specialization wouldn't crash due to constant expression.
+; RUN: opt -function-specialization -S < %s | FileCheck %s
+
+; CHECK-LABEL: @main(i64 %x, i1 %flag) {
+; CHECK:         entry:
+; CHECK-NEXT:      br i1 %flag, label %plus, label %minus
+; CHECK:         plus:
+; CHECK-NEXT:      [[TMP0:%.+]] = add i64 %x, 1
+; CHECH-NEXT:      br label %merge
+; CHECK:         minus:
+; CHECK-NEXT:      [[TMP1:%.+]] = sub i64 %x, 1
+; CHECK-NEXT:      br label %merge
+; CHECK:         merge:
+; CHECK-NEXT:      [[TMP2:%.+]] = phi i64 [ [[TMP0]], %plus ], [ [[TMP1]], %minus ]
+; CHECK-NEXT:      ret i64 [[TMP2]]
+; CHECK-NEXT:  }
+;
+
+%struct = type { i8, i16, i32, i64, i64}
+ at Global = internal constant %struct {i8 0, i16 1, i32 2, i64 3, i64 4}
+define internal i64 @zoo(i1 %flag) {
+entry:
+  br i1 %flag, label %plus, label %minus
+
+plus:
+  %arg = getelementptr %struct, %struct* @Global, i32 0, i32 3
+  %tmp0 = call i64 @func2(i64* %arg)
+  br label %merge
+
+minus:
+  %arg2 = getelementptr %struct, %struct* @Global, i32 0, i32 4
+  %tmp1 = call i64 @func2(i64* %arg2)
+  br label %merge
+
+merge:
+  %tmp2 = phi i64 [ %tmp0, %plus ], [ %tmp1, %minus]
+  ret i64 %tmp2
+}
+
+define internal i64 @func2(i64 *%x) {
+entry:
+  %val = ptrtoint i64* %x to i64
+  ret i64 %val
+}
+
+define internal i64 @func(i64 *%x, i64 (i64*)* %binop) {
+entry:
+  %tmp0 = call i64 %binop(i64* %x)
+  ret i64 %tmp0
+}
+
+define i64 @main() {
+    %1 = call i64 @zoo(i1 0)
+    %2 = call i64 @zoo(i1 1)
+    %3 = add i64 %1, %2
+    ret i64 %3
+}
\ No newline at end of file
Index: llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
===================================================================
--- llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
+++ llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
@@ -489,6 +489,11 @@
         }
       }
 
+      /// FIXME: Remove this once we update the solver after we replace
+      /// the constant.
+      if (isa<ConstantExpr>(V))
+        continue;
+
       if (isa<Constant>(V) && (Solver.getLatticeValueFor(V).isConstant() ||
                                EnableSpecializationForLiteralConstant))
         Constants.push_back(cast<Constant>(V));


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D107067.362750.patch
Type: text/x-patch
Size: 2505 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20210729/3ca93a79/attachment.bin>