X86: Remove test instructions proceeding shift by immediate instructions

Allow LLVM to take advantage of shift instructions that set the ZF flag,
making instructions that test the destination superfluous.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182454 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGen/X86/2012-08-17-legalizer-crash.ll

@@ -27,6 +27,5 @@ if.end:                                           ; preds = %if.then, %entry
 
 ; CHECK: fn1:
 ; CHECK: shrq $32, [[REG:%.*]]
-; CHECK: testq [[REG]], [[REG]]
 ; CHECK: je
 }

test/CodeGen/X86/cmp.ll

@@ -96,7 +96,6 @@ entry:
 ; CHECK: test7:
 ; CHECK-NOT: movabsq
 ; CHECK: shrq $32, %rdi
-; CHECK: testq %rdi, %rdi
 ; CHECK: sete
   %lnot = icmp ult i64 %res, 4294967296
   %lnot.ext = zext i1 %lnot to i32
@@ -119,7 +118,6 @@ entry:
 ; CHECK: test9:
 ; CHECK-NOT: movabsq
 ; CHECK: shrq $33, %rdi
-; CHECK: testq %rdi, %rdi
 ; CHECK: sete
   %lnot = icmp ult i64 %res, 8589934592
   %lnot.ext = zext i1 %lnot to i32
@@ -131,7 +129,6 @@ entry:
 ; CHECK: test10:
 ; CHECK-NOT: movabsq
 ; CHECK: shrq $32, %rdi
-; CHECK: testq %rdi, %rdi
 ; CHECK: setne
   %lnot = icmp uge i64 %res, 4294967296
   %lnot.ext = zext i1 %lnot to i32

test/CodeGen/X86/peep-test-4.ll

@@ -1,5 +1,6 @@
 ; RUN: llc < %s -mtriple=x86_64-pc-linux -mattr=+bmi,+bmi2,+popcnt | FileCheck %s
 declare void @foo(i32)
+declare void @foo64(i64)
 
 ; CHECK: neg:
 ; CHECK: negl %edi
@@ -55,6 +56,24 @@ return:
   ret void
 }
 
+; CHECK: shri:
+; CHECK: shrl $3, %edi
+; CHECK-NEXT: je
+; CHECK: jmp foo
+; CHECK: ret
+define void @shri(i32 %x) nounwind {
+  %ashr = lshr i32 %x, 3
+  %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
@@ -73,6 +92,24 @@ return:
   ret void
 }
 
+; CHECK: shli:
+; CHECK: shll $4, %edi
+; CHECK-NEXT: je
+; CHECK: jmp foo
+; CHECK: ret
+define void @shli(i32 %x) nounwind {
+  %shl = shl i32 %x, 4
+  %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