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[InstCombine] Fix unsafe PHINode cast and simplify logic in PointerReplacer #172332

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[InstCombine] Fix unsafe PHINode cast and simplify logic in PointerReplacer #172332

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632bf62
[InstCombine] Fix unsafe PHINode cast and simplify logic in PointerRe…
Dec 15, 2025
6621ac8
Added a test.
Dec 16, 2025
ba60d83
Added a new line at the end.
Dec 17, 2025
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12 changes: 6 additions & 6 deletions llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -296,12 +296,12 @@ bool PointerReplacer::collectUsers() {
/// TODO: Handle poison and null pointers for PHI and select.
// If all incoming values are available, mark this PHI as
// replacable and push it's users into the worklist.
bool IsReplaceable = true;
if (all_of(PHI->incoming_values(), [&](Value *V) {
if (!isa<Instruction>(V))
return IsReplaceable = false;
return isAvailable(cast<Instruction>(V));
})) {
bool IsReplaceable = all_of(PHI->incoming_values(), [](Value *V) {
return isa<Instruction>(V);
});
if (IsReplaceable && all_of(PHI->incoming_values(), [&](Value *V) {
return isAvailable(cast<Instruction>(V));
})) {
UsersToReplace.insert(PHI);
PushUsersToWorklist(PHI);
continue;
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29 changes: 29 additions & 0 deletions llvm/test/Transforms/InstCombine/alloca-phi-non-inst.ll
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@@ -0,0 +1,29 @@
; RUN: opt < %s -O1 -S | FileCheck %s

@__const.var1 = addrspace(4) constant <{ ptr addrspace(5), ptr addrspace(5), ptr addrspace(5), ptr addrspace(5) }> <{ ptr addrspace(5) addrspacecast (ptr null to ptr addrspace(5)), ptr addrspace(5) addrspacecast (ptr null to ptr addrspace(5)), ptr addrspace(5) addrspacecast (ptr null to ptr addrspace(5)), ptr addrspace(5) addrspacecast (ptr null to ptr addrspace(5)) }>
define void @test(i32 %0, i1 %tobool, ptr addrspace(4) %const_src) {
; CHECK: entry:
; CHECK-NEXT: br label %BS_LABEL_3
; CHECK: BS_LABEL_3:
; CHECK-NEXT: br label %BS_LABEL_3
entry:
%l_632 = alloca [4 x ptr addrspace(5)], align 4, addrspace(5)
switch i32 %0, label %sw.epilog [
i32 1, label %BS_LABEL_3
i32 0, label %BS_LABEL_3
]

sw.epilog: ; preds = %entry
call void @llvm.memcpy.p5.p4.i64(ptr addrspace(5) %l_632, ptr addrspace(4) @__const.var1, i64 16, i1 false)
%arrayidx = getelementptr inbounds [4 x ptr addrspace(5)], ptr addrspace(5) %l_632, i64 0, i64 3
br i1 %tobool, label %BS_LABEL_7, label %BS_LABEL_3

BS_LABEL_7: ; preds = %BS_LABEL_3, %sw.epilog
%l_631.1 = phi ptr addrspace(5) [ %arrayidx, %sw.epilog ], [ %l_631.0, %BS_LABEL_3 ]
br label %BS_LABEL_3

BS_LABEL_3: ; preds = %BS_LABEL_7, %sw.epilog, %entry, %entry
%l_631.0 = phi ptr addrspace(5) [ %l_631.1, %BS_LABEL_7 ], [ %arrayidx, %sw.epilog ], [ undef, %entry ], [ undef, %entry ]
%cmp = icmp ugt ptr addrspace(5) %l_631.0, null
br label %BS_LABEL_7
}