[clang] [flang] [llvm] [flang] Add -finit-local= to initialize automatic variables (PR #216164)

[via cfe-commits]

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+! Tests that -finit-local= handles all CHARACTER kind-mapping widths correctly
+! using the code unit's allocation stride (alignTo(ceil(charBits/8), ABI)),
+! and that LOGICAL sub-byte and non-byte-multiple mappings emit a controlled
+! diagnostic.
+!
+! LOGICAL sub-byte: --kind-mapping=l4:1 maps LOGICAL(4) to 1 bit.
+! APInt::getSplat(1, APInt(8, 0xAA)) asserts because the destination width is
+! less than 8; a TODO is emitted.
+!
+! LOGICAL non-byte-multiple: --kind-mapping=l4:12 maps LOGICAL(4) to 12 bits.
+! makeIntCst(12) would produce 0xAAA (i12), which stores as AA 0A -- the high
+! nibble of the second byte is not filled.  A TODO is emitted instead.
+!
+! All CHARACTER kind widths are now handled without diagnostics:
+!   a1:1  -- i1 rounds up to i8, stride = 1 byte (fills 1 byte per code unit)
+!   a1:12 -- i12 rounds up to i16, stride = 2 bytes
+!   a1:24 -- i24 rounds up to i32, stride = 4 bytes (was the motivating case:
+!             charBits/8 = 3 missed the last byte; stride = 4 is correct)
+!
+! RUN: %not_todo_cmd bbc -emit-hlfir --kind-mapping=l4:1 -finit-local=0xAA %s -o - 2>&1 | \
+! RUN:     FileCheck %s
+
+! CHECK: not yet implemented: -finit-local= with a sub-byte or non-byte-multiple LOGICAL kind mapping
+
+subroutine test_logical4_subbyte(res)
+  logical(kind=4) :: l
+  integer :: res
+  if (l) res = 1
+end subroutine
+
+! LOGICAL non-byte-multiple: --kind-mapping=l4:12 maps LOGICAL(4) to 12 bits.
+! makeIntCst(12) would splat 0xAA into i12 -> 0xAAA, which stores as AA 0A.
+! The guard (bits % 8 != 0) catches this and emits a TODO.
+!
+! RUN: %not_todo_cmd bbc -emit-hlfir --kind-mapping=l4:12 -finit-local=0xAA %s -o - 2>&1 | \
+! RUN:     FileCheck --check-prefix=LOG-NONBYTE %s
+
+! LOG-NONBYTE: not yet implemented: -finit-local= with a sub-byte or non-byte-multiple LOGICAL kind mapping
+
+subroutine test_logical4_nonbyte(res)
+  logical(kind=4) :: l
+  integer :: res
+  if (l) res = 1
+end subroutine
+
+! CHARACTER a1:1: i1 rounds up to i8 (stride = 1 byte).  No diagnostic.
+!
+! RUN: bbc -emit-hlfir --kind-mapping=a1:1 -finit-local=0xAA %s -o - 2>&1 | \
+! RUN:     FileCheck --check-prefix=CHAR-1BIT %s
+
+! CHAR-1BIT-NOT: not yet implemented
+! CHAR-1BIT: fir.do_loop
+
+subroutine test_char1_subbyte(res)
+  character(kind=1, len=2) :: c
+  integer :: res
+  res = ichar(c(1:1))
+end subroutine
+
+! CHARACTER non-byte-multiple cases (a1:12, a1:24): both runs stop at
+! test_char1_subbyte, which has the same declarations.  That subroutine
+! already covers the % 8 branch of the stride formula (a1:12 gives stride 2,
+! a1:24 gives stride 4).  A positive check that no diagnostic fires and a
+! fir.do_loop is emitted is sufficient.
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MattPD wrote:

Confirmed. The extent checks reject the old incorrect bounds.

https://github.com/llvm/llvm-project/pull/216164