[PATCH] [x86] Do not convert to cmp32 for Atom arch.
Sergey Okunev
sergey.k.okunev at gmail.com
Wed Mar 12 08:01:05 PDT 2014
Updated patch with added test case.
Hi grosbach,
http://llvm-reviews.chandlerc.com/D2824
CHANGE SINCE LAST DIFF
http://llvm-reviews.chandlerc.com/D2824?vs=7197&id=7771#toc
Files:
lib/Target/X86/X86ISelLowering.cpp
test/CodeGen/X86/atom-cmpb.ll
Index: lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- lib/Target/X86/X86ISelLowering.cpp
+++ lib/Target/X86/X86ISelLowering.cpp
@@ -9768,12 +9768,14 @@
if ((Op0.getValueType() == MVT::i8 || Op0.getValueType() == MVT::i16 ||
Op0.getValueType() == MVT::i32 || Op0.getValueType() == MVT::i64)) {
- // Do the comparison at i32 if it's smaller. This avoids subregister
- // aliasing issues. Keep the smaller reference if we're optimizing for
- // size, however, as that'll allow better folding of memory operations.
+ // Do the comparison at i32 if it's smaller, besides the Atom case.
+ // This avoids subregister aliasing issues. Keep the smaller reference
+ // if we're optimizing for size, however, as that'll allow better folding
+ // of memory operations.
if (Op0.getValueType() != MVT::i32 && Op0.getValueType() != MVT::i64 &&
!DAG.getMachineFunction().getFunction()->getAttributes().hasAttribute(
- AttributeSet::FunctionIndex, Attribute::MinSize)) {
+ AttributeSet::FunctionIndex, Attribute::MinSize) &&
+ !Subtarget->isAtom()) {
unsigned ExtendOp =
isX86CCUnsigned(X86CC) ? ISD::ZERO_EXTEND : ISD::SIGN_EXTEND;
Op0 = DAG.getNode(ExtendOp, dl, MVT::i32, Op0);
Index: test/CodeGen/X86/atom-cmpb.ll
===================================================================
--- /dev/null
+++ test/CodeGen/X86/atom-cmpb.ll
@@ -0,0 +1,52 @@
+; RUN: llc < %s -march=x86 -mcpu=atom | FileCheck %s
+; CHECK: movl
+; CHECK: movb
+; CHECK: movb
+; CHECK: movb
+; CHECK: cmpb
+; CHECK: notb
+; CHECK: notb
+; CHECK: notb
+; CHECK: movb
+; CHECK: cmpb
+; CHECK: movb
+; CHECK: cmpb
+
+; Test for checking of cancel conversion to cmp32 in Atom case
+; in function 'X86TargetLowering::EmitCmp'
+
+define i8 @run_test(i8* %rd_p) {
+entry:
+ %incdec.ptr = getelementptr inbounds i8* %rd_p, i64 1
+ %ld1 = load i8* %rd_p, align 1
+ %incdec.ptr1 = getelementptr inbounds i8* %rd_p, i64 2
+ %ld2 = load i8* %incdec.ptr, align 1
+ %incdec.ptr2 = getelementptr inbounds i8* %rd_p, i64 3
+ %ld3 = load i8* %incdec.ptr1, align 1
+ %x4 = xor i8 %ld1, -1
+ %x5 = xor i8 %ld2, -1
+ %x6 = xor i8 %ld3, -1
+ %cmp34 = icmp ult i8 %ld2, %ld1
+ br i1 %cmp34, label %if.then3, label %if.else
+
+if.then3:
+ %cmp3 = icmp ult i8 %x4, %x6
+ %.sink3 = select i1 %cmp3, i8 %x4, i8 %x6
+ br label %if.end4
+
+if.else:
+ %cmp4 = icmp ult i8 %x5, %x6
+ %.sink4 = select i1 %cmp4, i8 %x5, i8 %x6
+ br label %if.end4
+
+if.end4:
+ %xk = phi i8 [ %.sink3, %if.then3 ], [ %.sink4, %if.else ]
+ %sub7 = sub i8 %x4, %xk
+ %sub8 = sub i8 %x5, %xk
+ %sub9 = sub i8 %x6, %xk
+ %add10 = add i8 %sub7, %sub8
+ %res = add i8 %add10, %sub9
+ ret i8 %res
+
+}
+
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