From 23af697ae6b7217ac10f81ac8b95625c4ff42ecc Mon Sep 17 00:00:00 2001 From: Mehdi Amini Date: Wed, 11 Feb 2015 19:54:44 +0000 Subject: [PATCH] Reassociate: cannot negate a INT_MIN value Summary: When trying to canonicalize negative constants out of multiplication expressions, we need to check that the constant is not INT_MIN which cannot be negated. Reviewers: mcrosier Reviewed By: mcrosier Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D7286 From: Mehdi Amini git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228872 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/Reassociate.cpp | 2 +- test/Transforms/Reassociate/min_int.ll | 13 +++++++++++++ 2 files changed, 14 insertions(+), 1 deletion(-) create mode 100644 test/Transforms/Reassociate/min_int.ll diff --git a/lib/Transforms/Scalar/Reassociate.cpp b/lib/Transforms/Scalar/Reassociate.cpp index 0fd64e31dfe..98016b40c56 100644 --- a/lib/Transforms/Scalar/Reassociate.cpp +++ b/lib/Transforms/Scalar/Reassociate.cpp @@ -1991,7 +1991,7 @@ Instruction *Reassociate::canonicalizeNegConstExpr(Instruction *I) { Constant *C = C0 ? C0 : C1; unsigned ConstIdx = C0 ? 0 : 1; if (auto *CI = dyn_cast(C)) { - if (!CI->isNegative()) + if (!CI->isNegative() || CI->isMinValue(true)) return nullptr; } else if (auto *CF = dyn_cast(C)) { if (!CF->isNegative()) diff --git a/test/Transforms/Reassociate/min_int.ll b/test/Transforms/Reassociate/min_int.ll new file mode 100644 index 00000000000..52dab3a531f --- /dev/null +++ b/test/Transforms/Reassociate/min_int.ll @@ -0,0 +1,13 @@ +; RUN: opt < %s -reassociate -dce -S | FileCheck %s + +; MIN_INT cannot be negated during reassociation + +define i32 @minint(i32 %i) { +; CHECK: %mul = mul i32 %i, -2147483648 +; CHECK-NEXT: %add = add i32 %mul, 1 +; CHECK-NEXT: ret i32 %add + %mul = mul i32 %i, -2147483648 + %add = add i32 %mul, 1 + ret i32 %add +} + -- 2.34.1