[AtomicExpandPass] Widen partword atomicrmw or/xor/and before tryExpandAtomicRMW

This patch performs a widening transformation of bitwise atomicrmw 
{or,xor,and} and applies it prior to tryExpandAtomicRMW. This operates 
similarly to convertCmpXchgToIntegerType. For these operations, the i8/i16 
atomicrmw can be implemented in terms of the 32-bit atomicrmw by appropriately 
manipulating the operands. There is no functional change for the handling of 
partword or/xor, but the transformation for partword 'and' is new.

The advantage of performing this transformation early is that the same 
code-path can be used regardless of the approach used to expand the atomicrmw 
(AtomicExpansionKind). i.e. the same logic is used for 
AtomicExpansionKind::CmpXchg and can also be used by the intrinsic-based 
expansion in D47882.

Differential Revision: https://reviews.llvm.org/D48129

llvm-svn: 340027

1 files changed, 25 insertions, 0 deletions

diff --git a/llvm/test/Transforms/AtomicExpand/SPARC/partword.ll b/llvm/test/Transforms/AtomicExpand/SPARC/partword.ll
index 9963d17c242..74c05615d0b 100644
--- a/llvm/test/Transforms/AtomicExpand/SPARC/partword.ll
+++ b/llvm/test/Transforms/AtomicExpand/SPARC/partword.ll
@@ -147,6 +147,31 @@ entry:
   ret i16 %ret
 }
 
+; CHECK-LABEL: @test_or_i16(
+; (I'm going to just assert on the bits that differ from add, above.)
+; CHECK:atomicrmw.start:
+; CHECK:  %new = or i32 %loaded, %ValOperand_Shifted
+; CHECK:  %6 = cmpxchg i32* %AlignedAddr, i32 %loaded, i32 %new monotonic monotonic
+; CHECK:atomicrmw.end:
+define i16 @test_or_i16(i16* %arg, i16 %val) {
+entry:
+  %ret = atomicrmw or i16* %arg, i16 %val seq_cst
+  ret i16 %ret
+}
+
+; CHECK-LABEL: @test_and_i16(
+; (I'm going to just assert on the bits that differ from add, above.)
+; CHECK:  %AndOperand = or i32 %Inv_Mask, %ValOperand_Shifted
+; CHECK:atomicrmw.start:
+; CHECK:  %new = and i32 %loaded, %AndOperand
+; CHECK:  %6 = cmpxchg i32* %AlignedAddr, i32 %loaded, i32 %new monotonic monotonic
+; CHECK:atomicrmw.end:
+define i16 @test_and_i16(i16* %arg, i16 %val) {
+entry:
+  %ret = atomicrmw and i16* %arg, i16 %val seq_cst
+  ret i16 %ret
+}
+
 ; CHECK-LABEL: @test_min_i16(
 ; CHECK:atomicrmw.start:
 ; CHECK:  %6 = lshr i32 %loaded, %ShiftAmt