[X86] Model ADC/SBB with immediate 0 more accurately in the Haswell scheduler model

Haswell and possibly Sandybridge have an optimization for ADC/SBB with immediate 0 to use a single uop flow. This only applies GR16/GR32/GR64 with an 8-bit immediate. It does not apply to GR8. It also does not apply to the implicit AX/EAX/RAX forms.

Differential Revision: https://reviews.llvm.org/D59058

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@355635 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86SchedHaswell.td b/lib/Target/X86/X86SchedHaswell.td
index dc040e0e7d321e9f6ad2e1b4baa37a58c7904fdf..5fc838a2ce3fba3af07fdd43797ffe07fd7c7cbb 100644 (file)
--- a/lib/Target/X86/X86SchedHaswell.td
+++ b/lib/Target/X86/X86SchedHaswell.td
@@ -1848,4 +1848,34 @@ def: InstRW<[HWWriteResGroup192], (instrs VGATHERQPSrm,
 
 def: InstRW<[WriteZero], (instrs CLC)>;
 
+// The 0x83 ADC/SBB opcodes have special support for immediate 0 to only require
+// a single uop. It does not apply to the GR8 encoding. And only applies to the
+// 8-bit immediate since using larger immediate for 0 would be silly.
+// Unfortunately, this optimization does not apply to the AX/EAX/RAX short
+// encodings we convert to in MCInstLowering so we exclude AX/EAX/RAX here since
+// we schedule before that point.
+// TODO: Should we disable using the short encodings on these CPUs?
+def HWFastADC0 : MCSchedPredicate<
+  CheckAll<[
+    CheckImmOperand<2, 0>,              // Second MCOperand is Imm and has value 0.
+    CheckNot<CheckRegOperand<1, AX>>,   // First MCOperand is not register AX
+    CheckNot<CheckRegOperand<1, EAX>>,  // First MCOperand is not register EAX
+    CheckNot<CheckRegOperand<1, RAX>>   // First MCOperand is not register RAX
+  ]>
+>;
+
+def HWWriteADC0 : SchedWriteRes<[HWPort06]> {
+  let Latency = 1;
+  let NumMicroOps = 1;
+  let ResourceCycles = [1];
+}
+
+def HWWriteADC : SchedWriteVariant<[
+  SchedVar<HWFastADC0, [HWWriteADC0]>,
+  SchedVar<NoSchedPred, [WriteADC]>
+]>;
+
+def : InstRW<[HWWriteADC], (instrs ADC16ri8, ADC32ri8, ADC64ri8,
+                                      SBB16ri8, SBB32ri8, SBB64ri8)>;
+
 } // SchedModel

diff --git a/test/tools/llvm-mca/X86/Haswell/resources-x86_64.s b/test/tools/llvm-mca/X86/Haswell/resources-x86_64.s
index 948ca64a630b98a0a8621e349da074b870b10750..0c913a5107618a076da6e880d7dc007bb7667493 100644 (file)
--- a/test/tools/llvm-mca/X86/Haswell/resources-x86_64.s
+++ b/test/tools/llvm-mca/X86/Haswell/resources-x86_64.s
@@ -909,7 +909,7 @@ xorq (%rax), %rdi
 # CHECK-NEXT:  6      9     1.00    *      *            adcb   %sil, (%rax)
 # CHECK-NEXT:  3      7     0.50    *                   adcb   (%rax), %dil
 # CHECK-NEXT:  2      2     0.50                        adcw   $0, %ax
-# CHECK-NEXT:  2      2     0.50                        adcw   $0, %di
+# CHECK-NEXT:  1      1     0.50                        adcw   $0, %di
 # CHECK-NEXT:  6      9     1.00    *      *            adcw   $0, (%rax)
 # CHECK-NEXT:  2      2     0.50                        adcw   $511, %ax
 # CHECK-NEXT:  2      2     0.50                        adcw   $511, %di
@@ -920,7 +920,7 @@ xorq (%rax), %rdi
 # CHECK-NEXT:  6      9     1.00    *      *            adcw   %si, (%rax)
 # CHECK-NEXT:  3      7     0.50    *                   adcw   (%rax), %di
 # CHECK-NEXT:  2      2     0.50                        adcl   $0, %eax
-# CHECK-NEXT:  2      2     0.50                        adcl   $0, %edi
+# CHECK-NEXT:  1      1     0.50                        adcl   $0, %edi
 # CHECK-NEXT:  6      9     1.00    *      *            adcl   $0, (%rax)
 # CHECK-NEXT:  2      2     0.50                        adcl   $665536, %eax
 # CHECK-NEXT:  2      2     0.50                        adcl   $665536, %edi
@@ -931,7 +931,7 @@ xorq (%rax), %rdi
 # CHECK-NEXT:  6      9     1.00    *      *            adcl   %esi, (%rax)
 # CHECK-NEXT:  3      7     0.50    *                   adcl   (%rax), %edi
 # CHECK-NEXT:  2      2     0.50                        adcq   $0, %rax
-# CHECK-NEXT:  2      2     0.50                        adcq   $0, %rdi
+# CHECK-NEXT:  1      1     0.50                        adcq   $0, %rdi
 # CHECK-NEXT:  6      9     1.00    *      *            adcq   $0, (%rax)
 # CHECK-NEXT:  2      2     0.50                        adcq   $665536, %rax
 # CHECK-NEXT:  2      2     0.50                        adcq   $665536, %rdi
@@ -1472,7 +1472,7 @@ xorq (%rax), %rdi
 # CHECK-NEXT:  6      9     1.00    *      *            sbbb   %sil, (%rax)
 # CHECK-NEXT:  3      7     0.50    *                   sbbb   (%rax), %dil
 # CHECK-NEXT:  2      2     0.50                        sbbw   $0, %ax
-# CHECK-NEXT:  2      2     0.50                        sbbw   $0, %di
+# CHECK-NEXT:  1      1     0.50                        sbbw   $0, %di
 # CHECK-NEXT:  6      9     1.00    *      *            sbbw   $0, (%rax)
 # CHECK-NEXT:  2      2     0.50                        sbbw   $511, %ax
 # CHECK-NEXT:  2      2     0.50                        sbbw   $511, %di
@@ -1483,7 +1483,7 @@ xorq (%rax), %rdi
 # CHECK-NEXT:  6      9     1.00    *      *            sbbw   %si, (%rax)
 # CHECK-NEXT:  3      7     0.50    *                   sbbw   (%rax), %di
 # CHECK-NEXT:  2      2     0.50                        sbbl   $0, %eax
-# CHECK-NEXT:  2      2     0.50                        sbbl   $0, %edi
+# CHECK-NEXT:  1      1     0.50                        sbbl   $0, %edi
 # CHECK-NEXT:  6      9     1.00    *      *            sbbl   $0, (%rax)
 # CHECK-NEXT:  2      2     0.50                        sbbl   $665536, %eax
 # CHECK-NEXT:  2      2     0.50                        sbbl   $665536, %edi
@@ -1494,7 +1494,7 @@ xorq (%rax), %rdi
 # CHECK-NEXT:  6      9     1.00    *      *            sbbl   %esi, (%rax)
 # CHECK-NEXT:  3      7     0.50    *                   sbbl   (%rax), %edi
 # CHECK-NEXT:  2      2     0.50                        sbbq   $0, %rax
-# CHECK-NEXT:  2      2     0.50                        sbbq   $0, %rdi
+# CHECK-NEXT:  1      1     0.50                        sbbq   $0, %rdi
 # CHECK-NEXT:  6      9     1.00    *      *            sbbq   $0, (%rax)
 # CHECK-NEXT:  2      2     0.50                        sbbq   $665536, %rax
 # CHECK-NEXT:  2      2     0.50                        sbbq   $665536, %rdi
@@ -1693,7 +1693,7 @@ xorq (%rax), %rdi
 
 # CHECK:      Resource pressure per iteration:
 # CHECK-NEXT: [0]    [1]    [2]    [3]    [4]    [5]    [6]    [7]    [8]    [9]
-# CHECK-NEXT: 80.00   -     579.25 373.25 269.83 269.83 209.00 287.75 641.75 82.33
+# CHECK-NEXT: 80.00   -     577.75 371.75 269.83 269.83 209.00 286.25 640.25 82.33
 
 # CHECK:      Resource pressure by instruction:
 # CHECK-NEXT: [0]    [1]    [2]    [3]    [4]    [5]    [6]    [7]    [8]    [9]    Instructions:
@@ -1707,7 +1707,7 @@ xorq (%rax), %rdi
 # CHECK-NEXT:  -      -     1.25   0.25   0.83   0.83   1.00   0.25   1.25   0.33   adcb       %sil, (%rax)
 # CHECK-NEXT:  -      -     0.75   0.25   0.50   0.50    -     0.25   0.75    -     adcb       (%rax), %dil
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     adcw       $0, %ax
-# CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     adcw       $0, %di
+# CHECK-NEXT:  -      -     0.50    -      -      -      -      -     0.50    -     adcw       $0, %di
 # CHECK-NEXT:  -      -     1.25   0.25   0.83   0.83   1.00   0.25   1.25   0.33   adcw       $0, (%rax)
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     adcw       $511, %ax
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     adcw       $511, %di
@@ -1718,7 +1718,7 @@ xorq (%rax), %rdi
 # CHECK-NEXT:  -      -     1.25   0.25   0.83   0.83   1.00   0.25   1.25   0.33   adcw       %si, (%rax)
 # CHECK-NEXT:  -      -     0.75   0.25   0.50   0.50    -     0.25   0.75    -     adcw       (%rax), %di
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     adcl       $0, %eax
-# CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     adcl       $0, %edi
+# CHECK-NEXT:  -      -     0.50    -      -      -      -      -     0.50    -     adcl       $0, %edi
 # CHECK-NEXT:  -      -     1.25   0.25   0.83   0.83   1.00   0.25   1.25   0.33   adcl       $0, (%rax)
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     adcl       $665536, %eax
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     adcl       $665536, %edi
@@ -1729,7 +1729,7 @@ xorq (%rax), %rdi
 # CHECK-NEXT:  -      -     1.25   0.25   0.83   0.83   1.00   0.25   1.25   0.33   adcl       %esi, (%rax)
 # CHECK-NEXT:  -      -     0.75   0.25   0.50   0.50    -     0.25   0.75    -     adcl       (%rax), %edi
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     adcq       $0, %rax
-# CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     adcq       $0, %rdi
+# CHECK-NEXT:  -      -     0.50    -      -      -      -      -     0.50    -     adcq       $0, %rdi
 # CHECK-NEXT:  -      -     1.25   0.25   0.83   0.83   1.00   0.25   1.25   0.33   adcq       $0, (%rax)
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     adcq       $665536, %rax
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     adcq       $665536, %rdi
@@ -2270,7 +2270,7 @@ xorq (%rax), %rdi
 # CHECK-NEXT:  -      -     1.25   0.25   0.83   0.83   1.00   0.25   1.25   0.33   sbbb       %sil, (%rax)
 # CHECK-NEXT:  -      -     0.75   0.25   0.50   0.50    -     0.25   0.75    -     sbbb       (%rax), %dil
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     sbbw       $0, %ax
-# CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     sbbw       $0, %di
+# CHECK-NEXT:  -      -     0.50    -      -      -      -      -     0.50    -     sbbw       $0, %di
 # CHECK-NEXT:  -      -     1.25   0.25   0.83   0.83   1.00   0.25   1.25   0.33   sbbw       $0, (%rax)
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     sbbw       $511, %ax
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     sbbw       $511, %di
@@ -2281,7 +2281,7 @@ xorq (%rax), %rdi
 # CHECK-NEXT:  -      -     1.25   0.25   0.83   0.83   1.00   0.25   1.25   0.33   sbbw       %si, (%rax)
 # CHECK-NEXT:  -      -     0.75   0.25   0.50   0.50    -     0.25   0.75    -     sbbw       (%rax), %di
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     sbbl       $0, %eax
-# CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     sbbl       $0, %edi
+# CHECK-NEXT:  -      -     0.50    -      -      -      -      -     0.50    -     sbbl       $0, %edi
 # CHECK-NEXT:  -      -     1.25   0.25   0.83   0.83   1.00   0.25   1.25   0.33   sbbl       $0, (%rax)
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     sbbl       $665536, %eax
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     sbbl       $665536, %edi
@@ -2292,7 +2292,7 @@ xorq (%rax), %rdi
 # CHECK-NEXT:  -      -     1.25   0.25   0.83   0.83   1.00   0.25   1.25   0.33   sbbl       %esi, (%rax)
 # CHECK-NEXT:  -      -     0.75   0.25   0.50   0.50    -     0.25   0.75    -     sbbl       (%rax), %edi
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     sbbq       $0, %rax
-# CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     sbbq       $0, %rdi
+# CHECK-NEXT:  -      -     0.50    -      -      -      -      -     0.50    -     sbbq       $0, %rdi
 # CHECK-NEXT:  -      -     1.25   0.25   0.83   0.83   1.00   0.25   1.25   0.33   sbbq       $0, (%rax)
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     sbbq       $665536, %rax
 # CHECK-NEXT:  -      -     0.75   0.25    -      -      -     0.25   0.75    -     sbbq       $665536, %rdi