Start inferring side effect information more aggressively, and fix many bugs in the

x86 backend where instructions were not marked maystore/mayload, and perf issues where
instructions were not marked neverHasSideEffects.  It would be really nice if we could
write patterns for copy instructions.

I have audited all the x86 instructions down to MOVDQAmr.  The flags on others and on
other targets are probably not right in all cases, but no clients currently use this
info that are enabled by default.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45829 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 14 insertions, 1 deletions

diff --git a/lib/Target/X86/X86InstrMMX.td b/lib/Target/X86/X86InstrMMX.td
index 3362289326..3f2f1debbf 100644
--- a/lib/Target/X86/X86InstrMMX.td
+++ b/lib/Target/X86/X86InstrMMX.td
@@ -156,17 +156,21 @@ def MMX_FEMMS : MMXI<0x0E, RawFrm, (outs), (ins), "femms", [(int_x86_mmx_femms)]
 //===----------------------------------------------------------------------===//
 
 // Data Transfer Instructions
+let neverHasSideEffects = 1 in
 def MMX_MOVD64rr : MMXI<0x6E, MRMSrcReg, (outs VR64:$dst), (ins GR32:$src),
                         "movd\t{$src, $dst|$dst, $src}", []>;
-let isSimpleLoad = 1, isReMaterializable = 1, mayHaveSideEffects = 1 in
+let isSimpleLoad = 1, mayLoad = 1, isReMaterializable = 1, mayHaveSideEffects = 1 in
 def MMX_MOVD64rm : MMXI<0x6E, MRMSrcMem, (outs VR64:$dst), (ins i32mem:$src),
                         "movd\t{$src, $dst|$dst, $src}", []>;
+let mayStore = 1 in 
 def MMX_MOVD64mr : MMXI<0x7E, MRMDestMem, (outs), (ins i32mem:$dst, VR64:$src),
                         "movd\t{$src, $dst|$dst, $src}", []>;
 
+let neverHasSideEffects = 1 in
 def MMX_MOVD64to64rr : MMXRI<0x6E, MRMSrcReg, (outs VR64:$dst), (ins GR64:$src),
                              "movd\t{$src, $dst|$dst, $src}", []>;
 
+let neverHasSideEffects = 1 in
 def MMX_MOVQ64rr : MMXI<0x6F, MRMSrcReg, (outs VR64:$dst), (ins VR64:$src),
                         "movq\t{$src, $dst|$dst, $src}", []>;
 let isSimpleLoad = 1, isReMaterializable = 1, mayHaveSideEffects = 1 in
@@ -417,35 +421,44 @@ def MMX_PSHUFWmi : MMXIi8<0x70, MRMSrcMem,
                                     MMX_PSHUFW_shuffle_mask:$src2)))]>;
 
 // -- Conversion Instructions
+let neverHasSideEffects = 1 in {
 def MMX_CVTPD2PIrr  : MMX2I<0x2D, MRMSrcReg, (outs VR64:$dst), (ins VR128:$src),
                             "cvtpd2pi\t{$src, $dst|$dst, $src}", []>;
+let mayLoad = 1 in
 def MMX_CVTPD2PIrm  : MMX2I<0x2D, MRMSrcMem, (outs VR64:$dst), (ins f128mem:$src),
                             "cvtpd2pi\t{$src, $dst|$dst, $src}", []>;
 
 def MMX_CVTPI2PDrr  : MMX2I<0x2A, MRMSrcReg, (outs VR128:$dst), (ins VR64:$src),
                             "cvtpi2pd\t{$src, $dst|$dst, $src}", []>;
+let mayLoad = 1 in
 def MMX_CVTPI2PDrm  : MMX2I<0x2A, MRMSrcMem, (outs VR128:$dst), (ins i64mem:$src),
                             "cvtpi2pd\t{$src, $dst|$dst, $src}", []>;
 
 def MMX_CVTPI2PSrr  : MMXI<0x2A, MRMSrcReg, (outs VR128:$dst), (ins VR64:$src),
                            "cvtpi2ps\t{$src, $dst|$dst, $src}", []>;
+let mayLoad = 1 in
 def MMX_CVTPI2PSrm  : MMXI<0x2A, MRMSrcMem, (outs VR128:$dst), (ins i64mem:$src),
                            "cvtpi2ps\t{$src, $dst|$dst, $src}", []>;
 
 def MMX_CVTPS2PIrr  : MMXI<0x2D, MRMSrcReg, (outs VR64:$dst), (ins VR128:$src),
                            "cvtps2pi\t{$src, $dst|$dst, $src}", []>;
+let mayLoad = 1 in
 def MMX_CVTPS2PIrm  : MMXI<0x2D, MRMSrcMem, (outs VR64:$dst), (ins f64mem:$src),
                            "cvtps2pi\t{$src, $dst|$dst, $src}", []>;
 
 def MMX_CVTTPD2PIrr : MMX2I<0x2C, MRMSrcReg, (outs VR64:$dst), (ins VR128:$src),
                             "cvttpd2pi\t{$src, $dst|$dst, $src}", []>;
+let mayLoad = 1 in
 def MMX_CVTTPD2PIrm : MMX2I<0x2C, MRMSrcMem, (outs VR64:$dst), (ins f128mem:$src),
                             "cvttpd2pi\t{$src, $dst|$dst, $src}", []>;
 
 def MMX_CVTTPS2PIrr : MMXI<0x2C, MRMSrcReg, (outs VR64:$dst), (ins VR128:$src),
                            "cvttps2pi\t{$src, $dst|$dst, $src}", []>;
+let mayLoad = 1 in
 def MMX_CVTTPS2PIrm : MMXI<0x2C, MRMSrcMem, (outs VR64:$dst), (ins f64mem:$src),
                            "cvttps2pi\t{$src, $dst|$dst, $src}", []>;
+} // end neverHasSideEffects
+
 
 // Extract / Insert
 def MMX_X86pextrw : SDNode<"X86ISD::PEXTRW", SDTypeProfile<1, 2, []>, []>;