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[GVN] Fix use-after-free in load PRE with select available value (#69314
) replaceValuesPerBlockEntry() only handled simple and coerced load values, however the load may also be referenced by a select value. Additionally, I suspect that the previous code might have been incorrect if a load had an offset, as it always constructed the AvailableValue from scratch. Fixes #69301. (cherry picked from commit 7f1733a)
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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 3 | ||
; RUN: opt -S -passes=gvn < %s | FileCheck %s | ||
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; Make sure we don't have use-after-free due to dangling values in | ||
; select available value. | ||
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define i64 @test(i1 %c, ptr %p) { | ||
; CHECK-LABEL: define i64 @test | ||
; CHECK-SAME: (i1 [[C:%.*]], ptr [[P:%.*]]) { | ||
; CHECK-NEXT: entry: | ||
; CHECK-NEXT: br label [[LOOP:%.*]] | ||
; CHECK: loop: | ||
; CHECK-NEXT: [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[ADD:%.*]], [[LOOP_LATCH:%.*]] ] | ||
; CHECK-NEXT: [[PTR_IV:%.*]] = phi ptr [ [[P]], [[ENTRY]] ], [ [[SELECT:%.*]], [[LOOP_LATCH]] ] | ||
; CHECK-NEXT: [[ICMP:%.*]] = icmp eq i64 [[IV]], 0 | ||
; CHECK-NEXT: br i1 [[ICMP]], label [[LOOP_EXIT_CRIT_EDGE:%.*]], label [[LOOP_CONT:%.*]] | ||
; CHECK: loop.exit_crit_edge: | ||
; CHECK-NEXT: [[RES_PRE:%.*]] = load i64, ptr [[PTR_IV]], align 8 | ||
; CHECK-NEXT: br label [[EXIT:%.*]] | ||
; CHECK: loop.cont: | ||
; CHECK-NEXT: [[ADD]] = add i64 [[IV]], -1 | ||
; CHECK-NEXT: [[RES_PRE1:%.*]] = load i64, ptr [[PTR_IV]], align 8 | ||
; CHECK-NEXT: br i1 [[C]], label [[EXIT]], label [[LOOP_LATCH]] | ||
; CHECK: loop.latch: | ||
; CHECK-NEXT: [[LOAD6:%.*]] = load i64, ptr [[P]], align 8 | ||
; CHECK-NEXT: [[ICMP7:%.*]] = icmp ugt i64 [[RES_PRE1]], [[LOAD6]] | ||
; CHECK-NEXT: [[TMP0:%.*]] = select i1 [[ICMP7]], i64 [[RES_PRE1]], i64 [[LOAD6]] | ||
; CHECK-NEXT: [[SELECT]] = select i1 [[ICMP7]], ptr [[PTR_IV]], ptr [[P]] | ||
; CHECK-NEXT: br label [[LOOP]] | ||
; CHECK: exit: | ||
; CHECK-NEXT: [[RES:%.*]] = phi i64 [ [[RES_PRE]], [[LOOP_EXIT_CRIT_EDGE]] ], [ [[RES_PRE1]], [[LOOP_CONT]] ] | ||
; CHECK-NEXT: ret i64 [[RES]] | ||
; | ||
entry: | ||
br label %loop | ||
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loop: | ||
%iv = phi i64 [ 0, %entry ], [ %add, %loop.latch ] | ||
%ptr.iv = phi ptr [ %p, %entry ], [ %select, %loop.latch ] | ||
%icmp = icmp eq i64 %iv, 0 | ||
br i1 %icmp, label %exit, label %loop.cont | ||
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loop.cont: | ||
%add = add i64 %iv, -1 | ||
br i1 %c, label %exit, label %loop.latch | ||
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loop.latch: | ||
%load = load i64, ptr %ptr.iv, align 8 | ||
%load6 = load i64, ptr %p, align 8 | ||
%icmp7 = icmp ugt i64 %load, %load6 | ||
%select = select i1 %icmp7, ptr %ptr.iv, ptr %p | ||
br label %loop | ||
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exit: | ||
%res = load i64, ptr %ptr.iv, align 8 | ||
ret i64 %res | ||
} |