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LowerSubregs, and fix an x86-64 isel bug that this exposed. SUBREG_TO_REG for x86-64 implicit zero extension is only safe for isel to generate when the source is known to always have zeros in the high 32 bits. The EXTRACT_SUBREG instruction does not clear the high 32 bits. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54444 91177308-0d34-0410-b5e6-96231b3b80d8
11 lines
265 B
LLVM
11 lines
265 B
LLVM
; RUN: llvm-as < %s | llc -march=x86-64 | grep {movl %e.\*, %e.\*} | count 1
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; Don't eliminate or coalesce away the explicit zero-extension!
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define i64 @foo(i64 %a) {
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%b = add i64 %a, 4294967295
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%c = and i64 %b, 4294967295
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%d = add i64 %c, 1
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ret i64 %d
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}
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