X86: Remove redundant test instructions

Increase the number of instructions LLVM recognizes as setting the ZF
flag. This allows us to remove test instructions that redundantly
recalculate the flag.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181937 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 154 insertions, 0 deletions

diff --git a/test/CodeGen/X86/peep-test-4.ll b/test/CodeGen/X86/peep-test-4.ll
new file mode 100644
index 0000000000..91c37fbffb
--- /dev/null
+++ b/test/CodeGen/X86/peep-test-4.ll
@@ -0,0 +1,154 @@
+; RUN: llc < %s -march=x86-64 -mattr=+bmi,+bmi2,+popcnt | FileCheck %s
+declare void @foo(i32)
+
+; CHECK: neg:
+; CHECK: negl %edi
+; CHECK-NEXT: je
+; CHECK: jmp foo
+; CHECK: ret
+define void @neg(i32 %x) nounwind {
+  %sub = sub i32 0, %x
+  %cmp = icmp eq i32 %sub, 0
+  br i1 %cmp, label %return, label %bb
+
+bb:
+  tail call void @foo(i32 %sub)
+  br label %return
+
+return:
+  ret void
+}
+
+; CHECK: sar:
+; CHECK: sarl %edi
+; CHECK-NEXT: je
+; CHECK: jmp foo
+; CHECK: ret
+define void @sar(i32 %x) nounwind {
+  %ashr = ashr i32 %x, 1
+  %cmp = icmp eq i32 %ashr, 0
+  br i1 %cmp, label %return, label %bb
+
+bb:
+  tail call void @foo(i32 %ashr)
+  br label %return
+
+return:
+  ret void
+}
+
+; CHECK: shr:
+; CHECK: shrl %edi
+; CHECK-NEXT: je
+; CHECK: jmp foo
+; CHECK: ret
+define void @shr(i32 %x) nounwind {
+  %ashr = lshr i32 %x, 1
+  %cmp = icmp eq i32 %ashr, 0
+  br i1 %cmp, label %return, label %bb
+
+bb:
+  tail call void @foo(i32 %ashr)
+  br label %return
+
+return:
+  ret void
+}
+
+; CHECK: shl:
+; CHECK: addl %edi, %edi
+; CHECK-NEXT: je
+; CHECK: jmp foo
+; CHECK: ret
+define void @shl(i32 %x) nounwind {
+  %shl = shl i32 %x, 1
+  %cmp = icmp eq i32 %shl, 0
+  br i1 %cmp, label %return, label %bb
+
+bb:
+  tail call void @foo(i32 %shl)
+  br label %return
+
+return:
+  ret void
+}
+
+; CHECK: adc:
+; CHECK: movabsq $-9223372036854775808, %rax
+; CHECK-NEXT: addq  %rdi, %rax
+; CHECK-NEXT: adcq  $0, %rsi
+; CHECK-NEXT: sete  %al
+; CHECK-NEXT: ret
+define zeroext i1 @adc(i128 %x) nounwind {
+  %add = add i128 %x, 9223372036854775808
+  %cmp = icmp ult i128 %add, 18446744073709551616
+  ret i1 %cmp
+}
+
+; CHECK: sbb:
+; CHECK: cmpq  %rdx, %rdi
+; CHECK-NEXT: sbbq  %rcx, %rsi
+; CHECK-NEXT: setns %al
+; CHECK-NEXT: ret
+define zeroext i1 @sbb(i128 %x, i128 %y) nounwind {
+  %sub = sub i128 %x, %y
+  %cmp = icmp sge i128 %sub, 0
+  ret i1 %cmp
+}
+
+; CHECK: andn:
+; CHECK: andnl   %esi, %edi, %edi
+; CHECK-NEXT: je
+; CHECK: jmp foo
+; CHECK: ret
+define void @andn(i32 %x, i32 %y) nounwind {
+  %not = xor i32 %x, -1
+  %andn = and i32 %y, %not
+  %cmp = icmp eq i32 %andn, 0
+  br i1 %cmp, label %return, label %bb
+
+bb:
+  tail call void @foo(i32 %andn)
+  br label %return
+
+return:
+  ret void
+}
+
+; CHECK: bextr:
+; CHECK: bextrl   %esi, %edi, %edi
+; CHECK-NEXT: je
+; CHECK: jmp foo
+; CHECK: ret
+declare i32 @llvm.x86.bmi.bextr.32(i32, i32) nounwind readnone
+define void @bextr(i32 %x, i32 %y) nounwind {
+  %bextr = tail call i32 @llvm.x86.bmi.bextr.32(i32 %x, i32 %y)
+  %cmp = icmp eq i32 %bextr, 0
+  br i1 %cmp, label %return, label %bb
+
+bb:
+  tail call void @foo(i32 %bextr)
+  br label %return
+
+return:
+  ret void
+}
+
+; CHECK: popcnt:
+; CHECK: popcntl
+; CHECK-NEXT: je
+; CHECK: jmp foo
+; CHECK: ret
+declare i32 @llvm.ctpop.i32(i32) nounwind readnone
+define void @popcnt(i32 %x) nounwind {
+  %popcnt = tail call i32 @llvm.ctpop.i32(i32 %x)
+  %cmp = icmp eq i32 %popcnt, 0
+  br i1 %cmp, label %return, label %bb
+;
+bb:
+  tail call void @foo(i32 %popcnt)
+  br label %return
+;
+return:
+  ret void
+}