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authorChris Lattner <sabre@nondot.org>2005-04-12 02:54:39 +0000
committerChris Lattner <sabre@nondot.org>2005-04-12 02:54:39 +0000
commitfd1f1ee0baf9c808fdee14bdbfe76d4a5e66210d (patch)
tree10321072e8f584f4ccaa7f239423ac0582d17e3d /lib
parent5b95ed652fcfe578aa8af4e21318fca989164e21 (diff)
Remove some redundant checks, add a couple of new ones. This allows us to
compile this: int foo (unsigned long a, unsigned long long g) { return a >= g; } To: foo: movl 8(%esp), %eax cmpl %eax, 4(%esp) setae %al cmpl $0, 12(%esp) sete %cl andb %al, %cl movzbl %cl, %eax ret instead of: foo: movl 8(%esp), %eax cmpl %eax, 4(%esp) setae %al movzbw %al, %cx movl 12(%esp), %edx cmpl $0, %edx sete %al movzbw %al, %ax cmpl $0, %edx cmove %cx, %ax movzbl %al, %eax ret git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21244 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r--lib/CodeGen/SelectionDAG/SelectionDAG.cpp12
1 files changed, 5 insertions, 7 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 0243ebf5df3..634197c0f96 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -960,12 +960,6 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
if (VT == MVT::i1) { // Boolean SELECT
if (N2C) {
- if (N3C) {
- if (N2C->getValue()) // select C, 1, 0 -> C
- return N1;
- return getNode(ISD::XOR, VT, N1, N3); // select C, 0, 1 -> ~C
- }
-
if (N2C->getValue()) // select C, 1, X -> C | X
return getNode(ISD::OR, VT, N1, N3);
else // select C, 0, X -> ~C & X
@@ -980,6 +974,11 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
else // select C, X, 0 -> C & X
return getNode(ISD::AND, VT, N1, N2);
}
+
+ if (N1 == N2) // X ? X : Y --> X ? 1 : Y --> X | Y
+ return getNode(ISD::OR, VT, N1, N3);
+ if (N1 == N3) // X ? Y : X --> X ? Y : 0 --> X & Y
+ return getNode(ISD::AND, VT, N1, N2);
}
// If this is a selectcc, check to see if we can simplify the result.
@@ -1001,7 +1000,6 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
N2.getOperand(0) == N3)
return getNode(ISD::FABS, VT, N3);
}
-
}
break;
case ISD::BRCOND: