[SystemZ] Directly use CC result of compare-and-swap
In order to implement a test whether a compare-and-swap succeeded, the
SystemZ back-end currently emits a rather inefficient sequence of first
converting the CC result into an integer, and then testing that integer
against zero. This commit changes the back-end to simply directly test
the CC value set by the compare-and-swap instruction.
llvm-svn: 322988
diff --git a/llvm/test/CodeGen/SystemZ/cmpxchg-01.ll b/llvm/test/CodeGen/SystemZ/cmpxchg-01.ll
index b3084ad..82c6781 100644
--- a/llvm/test/CodeGen/SystemZ/cmpxchg-01.ll
+++ b/llvm/test/CodeGen/SystemZ/cmpxchg-01.ll
@@ -89,3 +89,83 @@
ret i32 %res
}
+
+declare void @g()
+
+; Check using the comparison result for a branch.
+; CHECK-LABEL: f4
+; CHECK-MAIN-LABEL: f4:
+; CHECK-MAIN: risbg [[RISBG:%r[1-9]+]], %r2, 0, 189, 0{{$}}
+; CHECK-MAIN-DAG: sll %r2, 3
+; CHECK-MAIN-DAG: l [[OLD:%r[0-9]+]], 0([[RISBG]])
+; CHECK-MAIN: [[LOOP:\.[^ ]*]]:
+; CHECK-MAIN: rll [[TMP:%r[0-9]+]], [[OLD]], 8(%r2)
+; CHECK-MAIN: risbg %r3, [[TMP]], 32, 55, 0
+; CHECK-MAIN: cr [[TMP]], %r3
+; CHECK-MAIN: jlh [[EXIT:\.[^ ]*]]
+; CHECK-MAIN: risbg %r4, [[TMP]], 32, 55, 0
+; CHECK-MAIN: rll [[NEW:%r[0-9]+]], %r4, -8({{%r[1-9]+}})
+; CHECK-MAIN: cs [[OLD]], [[NEW]], 0([[RISBG]])
+; CHECK-MAIN: jl [[LOOP]]
+; CHECK-MAIN: [[EXIT]]:
+; CHECK-MAIN-NEXT: jlh [[LABEL:\.[^ ]*]]
+; CHECK-MAIN: jg g
+; CHECK-MAIN: [[LABEL]]:
+; CHECK-MAIN: br %r14
+;
+; CHECK-SHIFT-LABEL: f4:
+; CHECK-SHIFT: sll %r2, 3
+; CHECK-SHIFT: lcr [[NEGSHIFT:%r[1-9]+]], %r2
+; CHECK-SHIFT: rll
+; CHECK-SHIFT: rll {{%r[0-9]+}}, %r4, -8([[NEGSHIFT]])
+define void @f4(i8 *%src, i8 %cmp, i8 %swap) {
+ %pair = cmpxchg i8 *%src, i8 %cmp, i8 %swap seq_cst seq_cst
+ %cond = extractvalue { i8, i1 } %pair, 1
+ br i1 %cond, label %call, label %exit
+
+call:
+ tail call void @g()
+ br label %exit
+
+exit:
+ ret void
+}
+
+; ... and the same with the inverted direction.
+; CHECK-MAIN-LABEL: f5:
+; CHECK-MAIN: risbg [[RISBG:%r[1-9]+]], %r2, 0, 189, 0{{$}}
+; CHECK-MAIN-DAG: sll %r2, 3
+; CHECK-MAIN-DAG: l [[OLD:%r[0-9]+]], 0([[RISBG]])
+; CHECK-MAIN: [[LOOP:\.[^ ]*]]:
+; CHECK-MAIN: rll [[TMP:%r[0-9]+]], [[OLD]], 8(%r2)
+; CHECK-MAIN: risbg %r3, [[TMP]], 32, 55, 0
+; CHECK-MAIN: cr [[TMP]], %r3
+; CHECK-MAIN: jlh [[EXIT:\.[^ ]*]]
+; CHECK-MAIN: risbg %r4, [[TMP]], 32, 55, 0
+; CHECK-MAIN: rll [[NEW:%r[0-9]+]], %r4, -8({{%r[1-9]+}})
+; CHECK-MAIN: cs [[OLD]], [[NEW]], 0([[RISBG]])
+; CHECK-MAIN: jl [[LOOP]]
+; CHECK-MAIN: [[EXIT]]:
+; CHECK-MAIN-NEXT: jlh [[LABEL:\.[^ ]*]]
+; CHECK-MAIN: br %r14
+; CHECK-MAIN: [[LABEL]]:
+; CHECK-MAIN: jg g
+;
+; CHECK-SHIFT-LABEL: f5:
+; CHECK-SHIFT: sll %r2, 3
+; CHECK-SHIFT: lcr [[NEGSHIFT:%r[1-9]+]], %r2
+; CHECK-SHIFT: rll
+; CHECK-SHIFT: rll {{%r[0-9]+}}, %r4, -8([[NEGSHIFT]])
+define void @f5(i8 *%src, i8 %cmp, i8 %swap) {
+ %pair = cmpxchg i8 *%src, i8 %cmp, i8 %swap seq_cst seq_cst
+ %cond = extractvalue { i8, i1 } %pair, 1
+ br i1 %cond, label %exit, label %call
+
+call:
+ tail call void @g()
+ br label %exit
+
+exit:
+ ret void
+}
+