[llvm] bda8d1a - [PatternMatch] Do not match constant expression trunc

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2024-06-03T14:27:40+02:00
New Revision: bda8d1ad72fc72f21f6c536692594376d00db8b6

URL: https://github.com/llvm/llvm-project/commit/bda8d1ad72fc72f21f6c536692594376d00db8b6
DIFF: https://github.com/llvm/llvm-project/commit/bda8d1ad72fc72f21f6c536692594376d00db8b6.diff

LOG: [PatternMatch] Do not match constant expression trunc

Similar to the change previously made for binops, make m_Trunc()
only match instructions, not constant expressions. This is more
likely to cause a crash than do something useful.

Fixes crash reported at:
https://github.com/llvm/llvm-project/pull/92885#issuecomment-2145034670

Added: 
    

Modified: 
    llvm/include/llvm/IR/PatternMatch.h
    llvm/test/Transforms/InstCombine/icmp-of-trunc-ext.ll

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/IR/PatternMatch.h b/llvm/include/llvm/IR/PatternMatch.h
index 0d6d86cb47e67..526b7258b8ab7 100644
--- a/llvm/include/llvm/IR/PatternMatch.h
+++ b/llvm/include/llvm/IR/PatternMatch.h
@@ -1948,8 +1948,8 @@ m_IntToPtr(const OpTy &Op) {
 
 /// Matches Trunc.
 template <typename OpTy>
-inline CastOperator_match<OpTy, Instruction::Trunc> m_Trunc(const OpTy &Op) {
-  return CastOperator_match<OpTy, Instruction::Trunc>(Op);
+inline CastInst_match<OpTy, TruncInst> m_Trunc(const OpTy &Op) {
+  return CastInst_match<OpTy, TruncInst>(Op);
 }
 
 /// Matches trunc nuw.
@@ -1967,7 +1967,7 @@ m_NSWTrunc(const OpTy &Op) {
 }
 
 template <typename OpTy>
-inline match_combine_or<CastOperator_match<OpTy, Instruction::Trunc>, OpTy>
+inline match_combine_or<CastInst_match<OpTy, TruncInst>, OpTy>
 m_TruncOrSelf(const OpTy &Op) {
   return m_CombineOr(m_Trunc(Op), Op);
 }

diff  --git a/llvm/test/Transforms/InstCombine/icmp-of-trunc-ext.ll b/llvm/test/Transforms/InstCombine/icmp-of-trunc-ext.ll
index a1757fbb84b23..c0cd3e775f68a 100644
--- a/llvm/test/Transforms/InstCombine/icmp-of-trunc-ext.ll
+++ b/llvm/test/Transforms/InstCombine/icmp-of-trunc-ext.ll
@@ -642,3 +642,17 @@ define i1 @test_slt_nuw(i32 %x, i16 %y) {
   %cond = icmp slt i8 %conv1, %conv2
   ret i1 %cond
 }
+
+ at foo = external global i8
+ at bar = external global i8
+
+define i1 @constexpr_trunc() {
+; CHECK-LABEL: @constexpr_trunc(
+; CHECK-NEXT:    [[CMP5:%.*]] = icmp ne i16 trunc (i64 sub (i64 sub (i64 ptrtoint (ptr @bar to i64), i64 ptrtoint (ptr @foo to i64)), i64 8) to i16), trunc (i64 sub (i64 sub (i64 0, i64 ptrtoint (ptr @foo to i64)), i64 8) to i16)
+; CHECK-NEXT:    ret i1 [[CMP5]]
+;
+  %conv = zext i16 trunc (i64 sub (i64 sub nuw nsw (i64 ptrtoint (ptr @bar to i64), i64 ptrtoint (ptr @foo to i64)), i64 8) to i16) to i32
+  %conv1 = zext i16 trunc (i64 sub (i64 sub nuw nsw (i64 0, i64 ptrtoint (ptr @foo to i64)), i64 8) to i16) to i32
+  %cmp5 = icmp ne i32 %conv, %conv1
+  ret i1 %cmp5
+}