[PowerPC] Relax the checking on AND/AND8 in isSignOrZeroExtended.

Separate the handling of AND/AND8 out from PHI/OR/ISEL checking. The reasoning
is the others need all their operands to be sign/zero extended for their output
to also be sign/zero extended. This is true for AND and sign-extension, but for
zero-extension we only need at least one of the input operands to be zero
extended for the result to also be zero extended.

Differential Revision: https://reviews.llvm.org/D39078

llvm-svn: 319289

1 files changed, 33 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/PowerPC/zext-and-cmp.ll b/llvm/test/CodeGen/PowerPC/zext-and-cmp.ll
new file mode 100644
index 00000000000..b06a384d73b
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/zext-and-cmp.ll
@@ -0,0 +1,33 @@
+; RUN: llc -verify-machineinstrs -mtriple=powerpc64le-unknown-linux-gnu  < %s | FileCheck %s
+
+; Test that we recognize that an 'and' instruction that feeds a comparison
+; to zero can be simplifed by using the record form when one of its operands
+; is known to be zero extended.
+
+@k = common local_unnamed_addr global i32 0, align 4
+
+; Function Attrs: norecurse nounwind
+define signext i32 @cmplwi(i32* nocapture readonly %p, i32* nocapture readonly %q, i32 signext %j, i32 signext %r10) {
+entry:
+  %0 = load i32, i32* %q, align 4
+  %shl = shl i32 %0, %j
+  %1 = load i32, i32* %p, align 4
+  %and = and i32 %shl, %r10
+  %and1 = and i32 %and, %1
+  %tobool = icmp eq i32 %and1, 0
+  br i1 %tobool, label %cleanup, label %if.then
+
+if.then:
+  store i32 %j, i32* @k, align 4
+  br label %cleanup
+
+cleanup:
+  %retval.0 = phi i32 [ 0, %if.then ], [ 1, %entry ]
+  ret i32 %retval.0
+}
+
+; CHECK-LABEL: cmplwi:
+; CHECK:      lwz [[T1:[0-9]+]], 0(3)
+; CHECK:      and. {{[0-9]+}}, {{[0-9]+}}, [[T1]]
+; CHECK-NOT:  cmplwi
+; CHECK-NEXT: beq      0,