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llvm-mirror/test/CodeGen/PowerPC/pr49092.ll
Nemanja Ivanovic e433159a3e [DAGCombine] Do not remove masking argument to FP16_TO_FP for some targets
As of commit 284f2bffc9bc5, the DAG Combiner gets rid of the masking of the
input to this node if the mask only keeps the bottom 16 bits. This is because
the underlying library function does not use the high order bits. However, on
PowerPC's ELFv2 ABI, it is the caller that is responsible for clearing the bits
from the register. Therefore, the library implementation of __gnu_h2f_ieee will
return an incorrect result if the bits aren't cleared.

This combine is desired for ARM (and possibly other targets) so this patch adds
a query to Target Lowering to check if this zeroing needs to be kept.

Fixes: https://bugs.llvm.org/show_bug.cgi?id=49092

Differential revision: https://reviews.llvm.org/D96283
2021-02-09 06:33:48 -06:00

40 lines
1.3 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc -mcpu=pwr8 -ppc-asm-full-reg-names -ppc-vsr-nums-as-vr \
; RUN: -mtriple=powerpc64le-unknown-unknown < %s | FileCheck %s
; RUN: llc -mcpu=pwr9 -ppc-asm-full-reg-names -ppc-vsr-nums-as-vr \
; RUN: -mtriple=powerpc64le-unknown-unknown < %s | FileCheck %s \
; RUN: -check-prefix=CHECK-P9
define dso_local half @test2(i64 %a, i64 %b) local_unnamed_addr #0 {
; CHECK-LABEL: test2:
; CHECK: # %bb.0: # %entry
; CHECK-NEXT: mflr r0
; CHECK-NEXT: std r0, 16(r1)
; CHECK-NEXT: stdu r1, -32(r1)
; CHECK-NEXT: add r3, r4, r3
; CHECK-NEXT: addi r3, r3, 11
; CHECK-NEXT: clrlwi r3, r3, 16
; CHECK-NEXT: bl __gnu_h2f_ieee
; CHECK-NEXT: nop
; CHECK-NEXT: addi r1, r1, 32
; CHECK-NEXT: ld r0, 16(r1)
; CHECK-NEXT: mtlr r0
; CHECK-NEXT: blr
;
; CHECK-P9-LABEL: test2:
; CHECK-P9: # %bb.0: # %entry
; CHECK-P9-NEXT: add r3, r4, r3
; CHECK-P9-NEXT: addi r3, r3, 11
; CHECK-P9-NEXT: clrlwi r3, r3, 16
; CHECK-P9-NEXT: mtfprwz f0, r3
; CHECK-P9-NEXT: xscvhpdp f1, f0
; CHECK-P9-NEXT: blr
entry:
%add = add i64 %b, %a
%0 = trunc i64 %add to i16
%conv = add i16 %0, 11
%call = bitcast i16 %conv to half
ret half %call
}
attributes #0 = { nounwind }