[X86] Memory folding for commutative instructions (updated)
This patch improves support for commutative instructions in the x86 memory folding implementation by attempting to fold a commuted version of the instruction if the original folding fails - if that folding fails as well the instruction is 're-commuted' back to its original order before returning.
Updated version of r219584 (reverted in r219595) - the commutation attempt now explicitly ensures that neither of the commuted source operands are tied to the destination operand / register, which was the source of all the regressions that occurred with the original patch attempt.
Added additional regression test case provided by Joerg Sonnenberger.
Differential Revision: http://reviews.llvm.org/D5818
llvm-svn: 220239
diff --git a/llvm/test/CodeGen/X86/avx1-stack-reload-folding.ll b/llvm/test/CodeGen/X86/avx1-stack-reload-folding.ll
new file mode 100644
index 0000000..5da1b4c
--- /dev/null
+++ b/llvm/test/CodeGen/X86/avx1-stack-reload-folding.ll
@@ -0,0 +1,16 @@
+; RUN: llc -O3 -disable-peephole -mcpu=corei7-avx -mattr=+avx < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-unknown"
+
+; Function Attrs: nounwind readonly uwtable
+define <32 x double> @_Z14vstack_foldDv32_dS_(<32 x double> %a, <32 x double> %b) #0 {
+ %1 = fadd <32 x double> %a, %b
+ %2 = fsub <32 x double> %a, %b
+ %3 = fmul <32 x double> %1, %2
+ ret <32 x double> %3
+
+ ;CHECK-NOT: vmovapd {{.*#+}} 32-byte Reload
+ ;CHECK: vmulpd {{[0-9]*}}(%rsp), {{%ymm[0-9][0-9]*}}, {{%ymm[0-9][0-9]*}} {{.*#+}} 32-byte Folded Reload
+ ;CHECK-NOT: vmovapd {{.*#+}} 32-byte Reload
+}
diff --git a/llvm/test/CodeGen/X86/fold-tied-op.ll b/llvm/test/CodeGen/X86/fold-tied-op.ll
new file mode 100644
index 0000000..a643d86
--- /dev/null
+++ b/llvm/test/CodeGen/X86/fold-tied-op.ll
@@ -0,0 +1,84 @@
+; RUN: llc -verify-machineinstrs -mtriple=i386--netbsd < %s | FileCheck %s
+; Regression test for http://reviews.llvm.org/D5701
+
+; ModuleID = 'xxhash.i'
+target datalayout = "e-m:e-p:32:32-f64:32:64-f80:32-n8:16:32-S128"
+target triple = "i386--netbsd"
+
+; CHECK-LABEL: fn1
+; CHECK: shldl {{.*#+}} 4-byte Folded Spill
+; CHECK: orl {{.*#+}} 4-byte Folded Reload
+; CHECK: shldl {{.*#+}} 4-byte Folded Spill
+; CHECK: orl {{.*#+}} 4-byte Folded Reload
+; CHECK: addl {{.*#+}} 4-byte Folded Reload
+; CHECK: imull {{.*#+}} 4-byte Folded Reload
+; CHECK: orl {{.*#+}} 4-byte Folded Reload
+; CHECK: retl
+
+%struct.XXH_state64_t = type { i32, i32, i64, i64, i64 }
+
+@a = common global i32 0, align 4
+@b = common global i64 0, align 8
+
+; Function Attrs: nounwind uwtable
+define i64 @fn1() #0 {
+entry:
+ %0 = load i32* @a, align 4, !tbaa !1
+ %1 = inttoptr i32 %0 to %struct.XXH_state64_t*
+ %total_len = getelementptr inbounds %struct.XXH_state64_t* %1, i32 0, i32 0
+ %2 = load i32* %total_len, align 4, !tbaa !5
+ %tobool = icmp eq i32 %2, 0
+ br i1 %tobool, label %if.else, label %if.then
+
+if.then: ; preds = %entry
+ %v3 = getelementptr inbounds %struct.XXH_state64_t* %1, i32 0, i32 3
+ %3 = load i64* %v3, align 4, !tbaa !8
+ %v4 = getelementptr inbounds %struct.XXH_state64_t* %1, i32 0, i32 4
+ %4 = load i64* %v4, align 4, !tbaa !9
+ %v2 = getelementptr inbounds %struct.XXH_state64_t* %1, i32 0, i32 2
+ %5 = load i64* %v2, align 4, !tbaa !10
+ %shl = shl i64 %5, 1
+ %or = or i64 %shl, %5
+ %shl2 = shl i64 %3, 2
+ %shr = lshr i64 %3, 1
+ %or3 = or i64 %shl2, %shr
+ %add = add i64 %or, %or3
+ %mul = mul i64 %4, -4417276706812531889
+ %shl4 = mul i64 %4, -8834553413625063778
+ %shr5 = ashr i64 %mul, 3
+ %or6 = or i64 %shr5, %shl4
+ %mul7 = mul nsw i64 %or6, 1400714785074694791
+ %xor = xor i64 %add, %mul7
+ store i64 %xor, i64* @b, align 8, !tbaa !11
+ %mul8 = mul nsw i64 %xor, 1400714785074694791
+ br label %if.end
+
+if.else: ; preds = %entry
+ %6 = load i64* @b, align 8, !tbaa !11
+ %xor10 = xor i64 %6, -4417276706812531889
+ %mul11 = mul nsw i64 %xor10, 400714785074694791
+ br label %if.end
+
+if.end: ; preds = %if.else, %if.then
+ %storemerge.in = phi i64 [ %mul11, %if.else ], [ %mul8, %if.then ]
+ %storemerge = add i64 %storemerge.in, -8796714831421723037
+ store i64 %storemerge, i64* @b, align 8, !tbaa !11
+ ret i64 undef
+}
+
+attributes #0 = { nounwind uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.ident = !{!0}
+
+!0 = metadata !{metadata !"clang version 3.6 (trunk 219587)"}
+!1 = metadata !{metadata !2, metadata !2, i64 0}
+!2 = metadata !{metadata !"int", metadata !3, i64 0}
+!3 = metadata !{metadata !"omnipotent char", metadata !4, i64 0}
+!4 = metadata !{metadata !"Simple C/C++ TBAA"}
+!5 = metadata !{metadata !6, metadata !2, i64 0}
+!6 = metadata !{metadata !"XXH_state64_t", metadata !2, i64 0, metadata !2, i64 4, metadata !7, i64 8, metadata !7, i64 16, metadata !7, i64 24}
+!7 = metadata !{metadata !"long long", metadata !3, i64 0}
+!8 = metadata !{metadata !6, metadata !7, i64 16}
+!9 = metadata !{metadata !6, metadata !7, i64 24}
+!10 = metadata !{metadata !6, metadata !7, i64 8}
+!11 = metadata !{metadata !7, metadata !7, i64 0}