bjoernager/rust
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Auto merge of #123602 - cjgillot:gvn-borrowed, r=oli-obk

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Account for immutably borrowed locals in MIR copy-prop and GVN

For the most part, we consider that immutably borrowed `Freeze` locals still fulfill SSA conditions. As the borrow is immutable, any use of the local will have the value given by the single assignment, and there can be no surprise.

This allows copy-prop to merge a non-borrowed local with a borrowed local. We chose to keep copy-classes heads unborrowed, as those may be easier to optimize in later passes.

This also allows to GVN the value behind an immutable borrow. If a SSA local is borrowed, dereferencing that borrow is equivalent to copying the local's value: re-executing the assignment between the borrow and the dereference would be UB.

r? `@ghost` for perf
This commit is contained in:
bors 2024-05-03 21:50:13 +00:00
commit d2d24e395a
30 changed files with 593 additions and 304 deletions
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6
tests/coverage/issue-83601.cov-map
View file

@ -1,12 +1,12 @@
Function name: issue_83601::main
Raw bytes (21): 0x[01, 01, 01, 05, 09, 03, 01, 06, 01, 02, 1c, 05, 03, 09, 01, 1c, 02, 02, 05, 03, 02]
Raw bytes (21): 0x[01, 01, 01, 05, 00, 03, 01, 06, 01, 02, 1c, 05, 03, 09, 01, 1c, 02, 02, 05, 03, 02]
Number of files: 1
- file 0 => global file 1
Number of expressions: 1
- expression 0 operands: lhs = Counter(1), rhs = Counter(2)
- expression 0 operands: lhs = Counter(1), rhs = Zero
Number of file 0 mappings: 3
- Code(Counter(0)) at (prev + 6, 1) to (start + 2, 28)
- Code(Counter(1)) at (prev + 3, 9) to (start + 1, 28)
- Code(Expression(0, Sub)) at (prev + 2, 5) to (start + 3, 2)
= (c1 - c2)
= (c1 - Zero)

22
tests/coverage/issue-84561.cov-map
View file

@ -77,22 +77,22 @@ Number of file 0 mappings: 1
- Code(Counter(0)) at (prev + 167, 9) to (start + 2, 10)
Function name: issue_84561::test3
Raw bytes (436): 0x[01, 01, 41, 05, 09, 0d, 00, 15, 19, 12, 00, 15, 19, 21, 00, 1e, 00, 21, 00, 31, 00, 3d, 41, 2e, 45, 3d, 41, 42, 49, 45, 00, 3f, 51, 42, 49, 45, 00, 5d, 8a, 01, 8f, 01, 5d, 92, 01, 55, 51, 00, 92, 01, 55, 51, 00, 8f, 01, 5d, 92, 01, 55, 51, 00, 87, 01, 61, 5d, 8a, 01, 8f, 01, 5d, 92, 01, 55, 51, 00, 82, 01, 65, 87, 01, 61, 5d, 8a, 01, 8f, 01, 5d, 92, 01, 55, 51, 00, 75, f6, 01, fb, 01, 79, 00, fe, 01, 82, 02, 00, 69, 6d, 00, fe, 01, 82, 02, 00, 69, 6d, 69, 6d, 82, 02, 00, 69, 6d, fb, 01, 79, 00, fe, 01, 82, 02, 00, 69, 6d, f3, 01, 7d, 75, f6, 01, fb, 01, 79, 00, fe, 01, 82, 02, 00, 69, 6d, ee, 01, 00, f3, 01, 7d, 75, f6, 01, fb, 01, 79, 00, fe, 01, 82, 02, 00, 69, 6d, 33, 01, 08, 01, 03, 1c, 05, 04, 09, 01, 1c, 02, 02, 05, 04, 1f, 0d, 05, 05, 00, 1f, 06, 01, 05, 00, 1f, 15, 01, 09, 01, 1c, 12, 02, 05, 00, 1f, 0e, 01, 05, 00, 0f, 00, 00, 20, 00, 30, 21, 01, 05, 03, 0f, 00, 03, 20, 00, 30, 00, 00, 33, 00, 41, 00, 00, 4b, 00, 5a, 1e, 01, 05, 00, 0f, 00, 05, 09, 03, 10, 00, 05, 0d, 00, 1b, 00, 02, 0d, 00, 1c, 1a, 04, 09, 05, 06, 31, 06, 05, 03, 06, 22, 04, 05, 03, 06, 3d, 04, 09, 04, 06, 2e, 05, 08, 00, 0f, 45, 01, 09, 03, 0a, 2a, 05, 09, 03, 0a, 3f, 05, 08, 00, 0f, 51, 01, 09, 00, 13, 00, 03, 0d, 00, 1d, 3a, 03, 09, 00, 13, 00, 03, 0d, 00, 1d, 87, 01, 03, 05, 00, 0f, 8f, 01, 01, 0c, 00, 13, 5d, 01, 0d, 00, 13, 8a, 01, 02, 0d, 00, 13, 82, 01, 04, 05, 02, 13, 65, 03, 0d, 00, 13, 7e, 02, 0d, 00, 13, f3, 01, 03, 05, 00, 0f, 69, 01, 0c, 00, 13, 6d, 01, 0d, 03, 0e, 75, 04, 0d, 00, 13, fb, 01, 02, 0d, 00, 17, 82, 02, 01, 14, 00, 1b, 00, 01, 15, 00, 1b, fe, 01, 02, 15, 00, 1b, f6, 01, 04, 0d, 00, 13, 7d, 03, 09, 00, 19, ee, 01, 02, 05, 00, 0f, ea, 01, 03, 09, 00, 22, 00, 02, 05, 00, 0f, 00, 03, 09, 00, 2c, 00, 02, 01, 00, 02]
Raw bytes (436): 0x[01, 01, 41, 05, 00, 0d, 00, 15, 00, 12, 00, 15, 00, 21, 00, 1e, 00, 21, 00, 31, 00, 3d, 00, 2e, 45, 3d, 00, 42, 49, 45, 00, 3f, 51, 42, 49, 45, 00, 5d, 8a, 01, 8f, 01, 5d, 92, 01, 55, 51, 00, 92, 01, 55, 51, 00, 8f, 01, 5d, 92, 01, 55, 51, 00, 87, 01, 61, 5d, 8a, 01, 8f, 01, 5d, 92, 01, 55, 51, 00, 82, 01, 65, 87, 01, 61, 5d, 8a, 01, 8f, 01, 5d, 92, 01, 55, 51, 00, 75, f6, 01, fb, 01, 79, 00, fe, 01, 82, 02, 00, 69, 6d, 00, fe, 01, 82, 02, 00, 69, 6d, 69, 6d, 82, 02, 00, 69, 6d, fb, 01, 79, 00, fe, 01, 82, 02, 00, 69, 6d, f3, 01, 7d, 75, f6, 01, fb, 01, 79, 00, fe, 01, 82, 02, 00, 69, 6d, ee, 01, 00, f3, 01, 7d, 75, f6, 01, fb, 01, 79, 00, fe, 01, 82, 02, 00, 69, 6d, 33, 01, 08, 01, 03, 1c, 05, 04, 09, 01, 1c, 02, 02, 05, 04, 1f, 0d, 05, 05, 00, 1f, 06, 01, 05, 00, 1f, 15, 01, 09, 01, 1c, 12, 02, 05, 00, 1f, 0e, 01, 05, 00, 0f, 00, 00, 20, 00, 30, 21, 01, 05, 03, 0f, 00, 03, 20, 00, 30, 00, 00, 33, 00, 41, 00, 00, 4b, 00, 5a, 1e, 01, 05, 00, 0f, 00, 05, 09, 03, 10, 00, 05, 0d, 00, 1b, 00, 02, 0d, 00, 1c, 1a, 04, 09, 05, 06, 31, 06, 05, 03, 06, 22, 04, 05, 03, 06, 3d, 04, 09, 04, 06, 2e, 05, 08, 00, 0f, 45, 01, 09, 03, 0a, 2a, 05, 09, 03, 0a, 3f, 05, 08, 00, 0f, 51, 01, 09, 00, 13, 00, 03, 0d, 00, 1d, 3a, 03, 09, 00, 13, 00, 03, 0d, 00, 1d, 87, 01, 03, 05, 00, 0f, 8f, 01, 01, 0c, 00, 13, 5d, 01, 0d, 00, 13, 8a, 01, 02, 0d, 00, 13, 82, 01, 04, 05, 02, 13, 65, 03, 0d, 00, 13, 7e, 02, 0d, 00, 13, f3, 01, 03, 05, 00, 0f, 69, 01, 0c, 00, 13, 6d, 01, 0d, 03, 0e, 75, 04, 0d, 00, 13, fb, 01, 02, 0d, 00, 17, 82, 02, 01, 14, 00, 1b, 00, 01, 15, 00, 1b, fe, 01, 02, 15, 00, 1b, f6, 01, 04, 0d, 00, 13, 7d, 03, 09, 00, 19, ee, 01, 02, 05, 00, 0f, ea, 01, 03, 09, 00, 22, 00, 02, 05, 00, 0f, 00, 03, 09, 00, 2c, 00, 02, 01, 00, 02]
Number of files: 1
- file 0 => global file 1
Number of expressions: 65
- expression 0 operands: lhs = Counter(1), rhs = Counter(2)
- expression 0 operands: lhs = Counter(1), rhs = Zero
- expression 1 operands: lhs = Counter(3), rhs = Zero
- expression 2 operands: lhs = Counter(5), rhs = Counter(6)
- expression 2 operands: lhs = Counter(5), rhs = Zero
- expression 3 operands: lhs = Expression(4, Sub), rhs = Zero
- expression 4 operands: lhs = Counter(5), rhs = Counter(6)
- expression 4 operands: lhs = Counter(5), rhs = Zero
- expression 5 operands: lhs = Counter(8), rhs = Zero
- expression 6 operands: lhs = Expression(7, Sub), rhs = Zero
- expression 7 operands: lhs = Counter(8), rhs = Zero
- expression 8 operands: lhs = Counter(12), rhs = Zero
- expression 9 operands: lhs = Counter(15), rhs = Counter(16)
- expression 9 operands: lhs = Counter(15), rhs = Zero
- expression 10 operands: lhs = Expression(11, Sub), rhs = Counter(17)
- expression 11 operands: lhs = Counter(15), rhs = Counter(16)
- expression 11 operands: lhs = Counter(15), rhs = Zero
- expression 12 operands: lhs = Expression(16, Sub), rhs = Counter(18)
- expression 13 operands: lhs = Counter(17), rhs = Zero
- expression 14 operands: lhs = Expression(15, Add), rhs = Counter(20)
@ -150,15 +150,15 @@ Number of file 0 mappings: 51
- Code(Counter(0)) at (prev + 8, 1) to (start + 3, 28)
- Code(Counter(1)) at (prev + 4, 9) to (start + 1, 28)
- Code(Expression(0, Sub)) at (prev + 2, 5) to (start + 4, 31)
= (c1 - c2)
= (c1 - Zero)
- Code(Counter(3)) at (prev + 5, 5) to (start + 0, 31)
- Code(Expression(1, Sub)) at (prev + 1, 5) to (start + 0, 31)
= (c3 - Zero)
- Code(Counter(5)) at (prev + 1, 9) to (start + 1, 28)
- Code(Expression(4, Sub)) at (prev + 2, 5) to (start + 0, 31)
= (c5 - c6)
= (c5 - Zero)
- Code(Expression(3, Sub)) at (prev + 1, 5) to (start + 0, 15)
= ((c5 - c6) - Zero)
= ((c5 - Zero) - Zero)
- Code(Zero) at (prev + 0, 32) to (start + 0, 48)
- Code(Counter(8)) at (prev + 1, 5) to (start + 3, 15)
- Code(Zero) at (prev + 3, 32) to (start + 0, 48)
@ -176,10 +176,10 @@ Number of file 0 mappings: 51
= (c12 - Zero)
- Code(Counter(15)) at (prev + 4, 9) to (start + 4, 6)
- Code(Expression(11, Sub)) at (prev + 5, 8) to (start + 0, 15)
= (c15 - c16)
= (c15 - Zero)
- Code(Counter(17)) at (prev + 1, 9) to (start + 3, 10)
- Code(Expression(10, Sub)) at (prev + 5, 9) to (start + 3, 10)
= ((c15 - c16) - c17)
= ((c15 - Zero) - c17)
- Code(Expression(15, Add)) at (prev + 5, 8) to (start + 0, 15)
= ((c17 - Zero) + c18)
- Code(Counter(20)) at (prev + 1, 9) to (start + 0, 19)