[llvm] 8daba2c - Skip negative length while inferring initializes attr (#120874)

[via llvm-commits]

Author: Haopeng Liu
Date: 2024-12-22T19:01:52-08:00
New Revision: 8daba2c13dc3f4856d064f57a2a56dcf4ea1d7b3

URL: https://github.com/llvm/llvm-project/commit/8daba2c13dc3f4856d064f57a2a56dcf4ea1d7b3
DIFF: https://github.com/llvm/llvm-project/commit/8daba2c13dc3f4856d064f57a2a56dcf4ea1d7b3.diff

LOG: Skip negative length while inferring initializes attr (#120874)

Bail out negative length while inferring initializes attr. Otherwise it
causes an assertion error:
`Attribute 'initializes' does not support unordered ranges`

Added: 
    

Modified: 
    llvm/lib/Transforms/IPO/FunctionAttrs.cpp
    llvm/test/Transforms/FunctionAttrs/initializes.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
index afb0ea72b269c8..fe9cca01a8f31f 100644
--- a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -633,7 +633,7 @@ ArgumentAccessInfo getArgmentAccessInfo(const Instruction *I,
       [](Value *Length,
          std::optional<int64_t> Offset) -> std::optional<ConstantRange> {
     auto *ConstantLength = dyn_cast<ConstantInt>(Length);
-    if (ConstantLength && Offset)
+    if (ConstantLength && Offset && !ConstantLength->isNegative())
       return ConstantRange(
           APInt(64, *Offset, true),
           APInt(64, *Offset + ConstantLength->getSExtValue(), true));

diff  --git a/llvm/test/Transforms/FunctionAttrs/initializes.ll b/llvm/test/Transforms/FunctionAttrs/initializes.ll
index 2aa8385fe4ca7b..c607fbeabb5087 100644
--- a/llvm/test/Transforms/FunctionAttrs/initializes.ll
+++ b/llvm/test/Transforms/FunctionAttrs/initializes.ll
@@ -423,6 +423,17 @@ define void @memset_offset(ptr %p) {
   ret void
 }
 
+define void @memset_neg(ptr %p) {
+; CHECK: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: write)
+; CHECK-LABEL: define void @memset_neg(
+; CHECK-SAME: ptr nocapture writeonly [[P:%.*]]) #[[ATTR0]] {
+; CHECK-NEXT:    call void @llvm.memset.p0.i64(ptr [[P]], i8 2, i64 -1, i1 false)
+; CHECK-NEXT:    ret void
+;
+  call void @llvm.memset(ptr %p, i8 2, i64 -1, i1 false)
+  ret void
+}
+
 define void @memset_volatile(ptr %p) {
 ; CHECK: Function Attrs: mustprogress nofree norecurse nounwind willreturn memory(argmem: write)
 ; CHECK-LABEL: define void @memset_volatile(