http://llvm.org/bugs/show_bug.cgi?id=12465
Bug #: 12465
Summary: __builtin_shufflevector produces incorrect IR when
mask argument is a vector
Product: clang
Version: trunk
Platform: PC
OS/Version: Linux
Status: NEW
Severity: normal
Priority: P
Component: LLVM Codegen
AssignedTo: [email protected]
ReportedBy: [email protected]
CC: [email protected]
Classification: Unclassified
Created attachment 8330
--> http://llvm.org/bugs/attachment.cgi?id=8330
Fix and test for __builtin_shufflevector code gen when mask is a vector
Found in top-of-tree at r154095.
ScalarExprEmitter::VisitShuffleVectorExpr produces incorrect IR when the mask
argument is a vector.
The *comment* is correct:
// newv = undef
// mask = mask & maskbits
// for each elt
// n = extract mask i
// x = extract val n
// newv = insert newv, x, i
But the code it generates is more like this:
// newv = undef
// mask = mask & maskbits
// for each elt
// n = extract mask i
// x = extract val n
// newv = insert newv, x, n (The "n" here is wrong.)
I could not find detailed enough lit-based tests to cover this case, but there
were none.
I'm attaching a fix and test. The test has a comment showing exactly where
things go wrong. Please consider for submission after editing.
--
Configure bugmail: http://llvm.org/bugs/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.
_______________________________________________
LLVMbugs mailing list
[email protected]
http://lists.cs.uiuc.edu/mailman/listinfo/llvmbugs
