This makes __builtin_shufflevector lowering force the result of the BIT_FIELD_REF lowpart operation to a temporary as to fulfil the IL verifier constraint that BIT_FIELD_REFs should be always in outermost handled component position. Trying to enforce this during gimplification isn't as straight-forward as here where we know we're dealing with an rvalue.
Bootstrap & regtest running on x86_64-unknown-linux-gnu - OK for trunk? Thanks, Richard. 2022-01-05 Richard Biener <rguent...@suse.de> PR middle-end/101530 gcc/c-family/ * c-common.c (c_build_shufflevector): Wrap the BIT_FIELD_REF in a TARGET_EXPR to force a temporary. gcc/testsuite/ * c-c++-common/builtin-shufflevector-3.c: New testcase. --- gcc/c-family/c-common.c | 5 +++++ .../c-c++-common/builtin-shufflevector-3.c | 15 +++++++++++++++ 2 files changed, 20 insertions(+) create mode 100644 gcc/testsuite/c-c++-common/builtin-shufflevector-3.c diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c index 13341fa315e..64209303d54 100644 --- a/gcc/c-family/c-common.c +++ b/gcc/c-family/c-common.c @@ -1243,6 +1243,11 @@ c_build_shufflevector (location_t loc, tree v0, tree v1, tree lpartt = build_vector_type (TREE_TYPE (ret_type), mask.length ()); ret = build3_loc (loc, BIT_FIELD_REF, lpartt, ret, TYPE_SIZE (lpartt), bitsize_zero_node); + /* Wrap the lowpart operation in a TARGET_EXPR so it gets a separate + temporary during gimplification. See PR101530 for cases where + we'd otherwise end up with non-toplevel BIT_FIELD_REFs. */ + tree tem = create_tmp_var_raw (lpartt); + ret = build4 (TARGET_EXPR, lpartt, tem, ret, NULL_TREE, NULL_TREE); } if (!c_dialect_cxx () && !wrap) diff --git a/gcc/testsuite/c-c++-common/builtin-shufflevector-3.c b/gcc/testsuite/c-c++-common/builtin-shufflevector-3.c new file mode 100644 index 00000000000..0c9bda689ef --- /dev/null +++ b/gcc/testsuite/c-c++-common/builtin-shufflevector-3.c @@ -0,0 +1,15 @@ +/* { dg-do compile } */ + +typedef int __attribute__((__vector_size__ (sizeof(int)*4))) V; + +int +foo(V v, int i) +{ + return __builtin_shufflevector (v, v, 2, 3)[i]; +} + +int +bar(V v, int i) +{ + return __builtin_shufflevector(v, v, 4)[0] & i; +} -- 2.31.1