X86 Peephole: fold loads to the source register operand if possible.

Machine CSE and other optimizations can remove instructions so folding
is possible at peephole while not possible at ISel.

This patch is a rework of r160919 and was tested on clang self-host on my local
machine.

rdar://10554090 and rdar://11873276


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161152 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 23 insertions, 43 deletions

diff --git a/test/CodeGen/X86/sse-minmax.ll b/test/CodeGen/X86/sse-minmax.ll
index 4405f68451..5d3dbce1df 100644
--- a/test/CodeGen/X86/sse-minmax.ll
+++ b/test/CodeGen/X86/sse-minmax.ll
@@ -1,6 +1,6 @@
-; RUN: llc < %s -march=x86-64 -mcpu=nehalem -asm-verbose=false  | FileCheck %s
-; RUN: llc < %s -march=x86-64 -mcpu=nehalem -asm-verbose=false -enable-unsafe-fp-math -enable-no-nans-fp-math  | FileCheck -check-prefix=UNSAFE %s
-; RUN: llc < %s -march=x86-64 -mcpu=nehalem -asm-verbose=false -enable-no-nans-fp-math  | FileCheck -check-prefix=FINITE %s
+; RUN: llc < %s -march=x86-64 -mtriple=x86_64-apple-darwin -mcpu=nehalem -asm-verbose=false  | FileCheck %s
+; RUN: llc < %s -march=x86-64 -mtriple=x86_64-apple-darwin -mcpu=nehalem -asm-verbose=false -enable-unsafe-fp-math -enable-no-nans-fp-math  | FileCheck -check-prefix=UNSAFE %s
+; RUN: llc < %s -march=x86-64 -mtriple=x86_64-apple-darwin -mcpu=nehalem -asm-verbose=false -enable-no-nans-fp-math  | FileCheck -check-prefix=FINITE %s
 
 ; Some of these patterns can be matched as SSE min or max. Some of
 ; then can be matched provided that the operands are swapped.
@@ -137,16 +137,13 @@ define double @ole_inverse(double %x, double %y) nounwind {
 }
 
 ; CHECK:      ogt_x:
-; CHECK-NEXT: xorp{{[sd]}} %xmm1, %xmm1
-; CHECK-NEXT: maxsd %xmm1, %xmm0
+; CHECK-NEXT: maxsd LCP{{.*}}(%rip), %xmm0
 ; CHECK-NEXT: ret
 ; UNSAFE:      ogt_x:
-; UNSAFE-NEXT: xorp{{[sd]}} %xmm1, %xmm1
-; UNSAFE-NEXT: maxsd %xmm1, %xmm0
+; UNSAFE-NEXT: maxsd LCP{{.*}}(%rip), %xmm0
 ; UNSAFE-NEXT: ret
 ; FINITE:      ogt_x:
-; FINITE-NEXT: xorp{{[sd]}} %xmm1, %xmm1
-; FINITE-NEXT: maxsd %xmm1, %xmm0
+; FINITE-NEXT: maxsd LCP{{.*}}(%rip), %xmm0
 ; FINITE-NEXT: ret
 define double @ogt_x(double %x) nounwind {
   %c = fcmp ogt double %x, 0.000000e+00
@@ -155,16 +152,13 @@ define double @ogt_x(double %x) nounwind {
 }
 
 ; CHECK:      olt_x:
-; CHECK-NEXT: xorp{{[sd]}} %xmm1, %xmm1
-; CHECK-NEXT: minsd %xmm1, %xmm0
+; CHECK-NEXT: minsd LCP{{.*}}(%rip), %xmm0
 ; CHECK-NEXT: ret
 ; UNSAFE:      olt_x:
-; UNSAFE-NEXT: xorp{{[sd]}} %xmm1, %xmm1
-; UNSAFE-NEXT: minsd %xmm1, %xmm0
+; UNSAFE-NEXT: minsd LCP{{.*}}(%rip), %xmm0
 ; UNSAFE-NEXT: ret
 ; FINITE:      olt_x:
-; FINITE-NEXT: xorp{{[sd]}} %xmm1, %xmm1
-; FINITE-NEXT: minsd %xmm1, %xmm0
+; FINITE-NEXT: minsd LCP{{.*}}(%rip), %xmm0
 ; FINITE-NEXT: ret
 define double @olt_x(double %x) nounwind {
   %c = fcmp olt double %x, 0.000000e+00
@@ -217,12 +211,10 @@ define double @olt_inverse_x(double %x) nounwind {
 ; CHECK:      oge_x:
 ; CHECK:      ucomisd %xmm1, %xmm0
 ; UNSAFE:      oge_x:
-; UNSAFE-NEXT: xorp{{[sd]}}   %xmm1, %xmm1
-; UNSAFE-NEXT: maxsd   %xmm1, %xmm0
+; UNSAFE-NEXT: maxsd   LCP{{.*}}(%rip), %xmm0
 ; UNSAFE-NEXT: ret
 ; FINITE:      oge_x:
-; FINITE-NEXT: xorp{{[sd]}}   %xmm1, %xmm1
-; FINITE-NEXT: maxsd   %xmm1, %xmm0
+; FINITE-NEXT: maxsd   LCP{{.*}}(%rip), %xmm0
 ; FINITE-NEXT: ret
 define double @oge_x(double %x) nounwind {
   %c = fcmp oge double %x, 0.000000e+00
@@ -233,12 +225,10 @@ define double @oge_x(double %x) nounwind {
 ; CHECK:      ole_x:
 ; CHECK:      ucomisd %xmm0, %xmm1
 ; UNSAFE:      ole_x:
-; UNSAFE-NEXT: xorp{{[sd]}} %xmm1, %xmm1
-; UNSAFE-NEXT: minsd %xmm1, %xmm0
+; UNSAFE-NEXT: minsd LCP{{.*}}(%rip), %xmm0
 ; UNSAFE-NEXT: ret
 ; FINITE:      ole_x:
-; FINITE-NEXT: xorp{{[sd]}} %xmm1, %xmm1
-; FINITE-NEXT: minsd %xmm1, %xmm0
+; FINITE-NEXT: minsd LCP{{.*}}(%rip), %xmm0
 ; FINITE-NEXT: ret
 define double @ole_x(double %x) nounwind {
   %c = fcmp ole double %x, 0.000000e+00
@@ -411,12 +401,10 @@ define double @ule_inverse(double %x, double %y) nounwind {
 ; CHECK:      ugt_x:
 ; CHECK:      ucomisd %xmm0, %xmm1
 ; UNSAFE:      ugt_x:
-; UNSAFE-NEXT: xorp{{[sd]}}   %xmm1, %xmm1
-; UNSAFE-NEXT: maxsd   %xmm1, %xmm0
+; UNSAFE-NEXT: maxsd   LCP{{.*}}(%rip), %xmm0
 ; UNSAFE-NEXT: ret
 ; FINITE:      ugt_x:
-; FINITE-NEXT: xorp{{[sd]}}   %xmm1, %xmm1
-; FINITE-NEXT: maxsd   %xmm1, %xmm0
+; FINITE-NEXT: maxsd   LCP{{.*}}(%rip), %xmm0
 ; FINITE-NEXT: ret
 define double @ugt_x(double %x) nounwind {
   %c = fcmp ugt double %x, 0.000000e+00
@@ -427,12 +415,10 @@ define double @ugt_x(double %x) nounwind {
 ; CHECK:      ult_x:
 ; CHECK:      ucomisd %xmm1, %xmm0
 ; UNSAFE:      ult_x:
-; UNSAFE-NEXT: xorp{{[sd]}}   %xmm1, %xmm1
-; UNSAFE-NEXT: minsd   %xmm1, %xmm0
+; UNSAFE-NEXT: minsd   LCP{{.*}}(%rip), %xmm0
 ; UNSAFE-NEXT: ret
 ; FINITE:      ult_x:
-; FINITE-NEXT: xorp{{[sd]}}   %xmm1, %xmm1
-; FINITE-NEXT: minsd   %xmm1, %xmm0
+; FINITE-NEXT: minsd   LCP{{.*}}(%rip), %xmm0
 ; FINITE-NEXT: ret
 define double @ult_x(double %x) nounwind {
   %c = fcmp ult double %x, 0.000000e+00
@@ -482,12 +468,10 @@ define double @ult_inverse_x(double %x) nounwind {
 ; CHECK-NEXT: movap{{[sd]}} %xmm1, %xmm0
 ; CHECK-NEXT: ret
 ; UNSAFE:      uge_x:
-; UNSAFE-NEXT: xorp{{[sd]}}  %xmm1, %xmm1
-; UNSAFE-NEXT: maxsd  %xmm1, %xmm0
+; UNSAFE-NEXT: maxsd  LCP{{.*}}(%rip), %xmm0
 ; UNSAFE-NEXT: ret
 ; FINITE:      uge_x:
-; FINITE-NEXT: xorp{{[sd]}}  %xmm1, %xmm1
-; FINITE-NEXT: maxsd  %xmm1, %xmm0
+; FINITE-NEXT: maxsd  LCP{{.*}}(%rip), %xmm0
 ; FINITE-NEXT: ret
 define double @uge_x(double %x) nounwind {
   %c = fcmp uge double %x, 0.000000e+00
@@ -501,12 +485,10 @@ define double @uge_x(double %x) nounwind {
 ; CHECK-NEXT: movap{{[sd]}} %xmm1, %xmm0
 ; CHECK-NEXT: ret
 ; UNSAFE:      ule_x:
-; UNSAFE-NEXT: xorp{{[sd]}}  %xmm1, %xmm1
-; UNSAFE-NEXT: minsd  %xmm1, %xmm0
+; UNSAFE-NEXT: minsd  LCP{{.*}}(%rip), %xmm0
 ; UNSAFE-NEXT: ret
 ; FINITE:      ule_x:
-; FINITE-NEXT: xorp{{[sd]}}  %xmm1, %xmm1
-; FINITE-NEXT: minsd  %xmm1, %xmm0
+; FINITE-NEXT: minsd  LCP{{.*}}(%rip), %xmm0
 ; FINITE-NEXT: ret
 define double @ule_x(double %x) nounwind {
   %c = fcmp ule double %x, 0.000000e+00
@@ -515,8 +497,7 @@ define double @ule_x(double %x) nounwind {
 }
 
 ; CHECK:      uge_inverse_x:
-; CHECK-NEXT: xorp{{[sd]}} %xmm1, %xmm1
-; CHECK-NEXT: minsd %xmm1, %xmm0
+; CHECK-NEXT: minsd LCP{{.*}}(%rip), %xmm0
 ; CHECK-NEXT: ret
 ; UNSAFE:      uge_inverse_x:
 ; UNSAFE-NEXT: xorp{{[sd]}} %xmm1, %xmm1
@@ -535,8 +516,7 @@ define double @uge_inverse_x(double %x) nounwind {
 }
 
 ; CHECK:      ule_inverse_x:
-; CHECK-NEXT: xorp{{[sd]}} %xmm1, %xmm1
-; CHECK-NEXT: maxsd %xmm1, %xmm0
+; CHECK-NEXT: maxsd LCP{{.*}}(%rip), %xmm0
 ; CHECK-NEXT: ret
 ; UNSAFE:      ule_inverse_x:
 ; UNSAFE-NEXT: xorp{{[sd]}} %xmm1, %xmm1