[TargetLowering] expandFP_TO_UINT - avoid FPE due to out of range conversion (PR17686)

PR17686 demonstrates that for some targets FP exceptions can fire in cases where the FP_TO_UINT is expanded using a FP_TO_SINT instruction.

The existing code converts both the inrange and outofrange cases using FP_TO_SINT and then selects the result, this patch changes this for 'strict' cases to pre-select the FP_TO_SINT input and the offset adjustment.

The X87 cases don't need the strict flag but generates much nicer code with it....

Differential Revision: https://reviews.llvm.org/D53794

llvm-svn: 348251

2 files changed, 69 insertions, 119 deletions

diff --git a/llvm/test/CodeGen/X86/fp-cvt.ll b/llvm/test/CodeGen/X86/fp-cvt.ll
index 7a4d303163a..ab3d40ddcaa 100644
--- a/llvm/test/CodeGen/X86/fp-cvt.ll
+++ b/llvm/test/CodeGen/X86/fp-cvt.ll
@@ -483,29 +483,20 @@ define i64 @fptoui_i64_fp80(x86_fp80 %a0) nounwind {
 ; X64-X87-NEXT:    flds {{.*}}(%rip)
 ; X64-X87-NEXT:    fld %st(1)
 ; X64-X87-NEXT:    fsub %st(1)
+; X64-X87-NEXT:    xorl %eax, %eax
+; X64-X87-NEXT:    fxch %st(1)
+; X64-X87-NEXT:    fucompi %st(2)
+; X64-X87-NEXT:    fcmovnbe %st(1), %st(0)
+; X64-X87-NEXT:    fstp %st(1)
 ; X64-X87-NEXT:    fnstcw -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    movzwl -{{[0-9]+}}(%rsp), %eax
-; X64-X87-NEXT:    movw $3199, -{{[0-9]+}}(%rsp) # imm = 0xC7F
-; X64-X87-NEXT:    fldcw -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    movw %ax, -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    fistpll -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    fldcw -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    fnstcw -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    movzwl -{{[0-9]+}}(%rsp), %eax
+; X64-X87-NEXT:    movzwl -{{[0-9]+}}(%rsp), %ecx
 ; X64-X87-NEXT:    movw $3199, -{{[0-9]+}}(%rsp) # imm = 0xC7F
 ; X64-X87-NEXT:    fldcw -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    movw %ax, -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    fld %st(1)
+; X64-X87-NEXT:    movw %cx, -{{[0-9]+}}(%rsp)
 ; X64-X87-NEXT:    fistpll -{{[0-9]+}}(%rsp)
 ; X64-X87-NEXT:    fldcw -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    fucompi %st(1)
-; X64-X87-NEXT:    fstp %st(0)
-; X64-X87-NEXT:    jbe .LBB10_1
-; X64-X87-NEXT:  # %bb.2:
-; X64-X87-NEXT:    movq -{{[0-9]+}}(%rsp), %rax
-; X64-X87-NEXT:    retq
-; X64-X87-NEXT:  .LBB10_1:
-; X64-X87-NEXT:    movabsq $-9223372036854775808, %rax # imm = 0x8000000000000000
+; X64-X87-NEXT:    setbe %al
+; X64-X87-NEXT:    shlq $63, %rax
 ; X64-X87-NEXT:    xorq -{{[0-9]+}}(%rsp), %rax
 ; X64-X87-NEXT:    retq
 ;
@@ -515,17 +506,14 @@ define i64 @fptoui_i64_fp80(x86_fp80 %a0) nounwind {
 ; X64-SSSE3-NEXT:    flds {{.*}}(%rip)
 ; X64-SSSE3-NEXT:    fld %st(1)
 ; X64-SSSE3-NEXT:    fsub %st(1)
+; X64-SSSE3-NEXT:    xorl %eax, %eax
+; X64-SSSE3-NEXT:    fxch %st(1)
+; X64-SSSE3-NEXT:    fucompi %st(2)
+; X64-SSSE3-NEXT:    fcmovnbe %st(1), %st(0)
+; X64-SSSE3-NEXT:    fstp %st(1)
 ; X64-SSSE3-NEXT:    fisttpll -{{[0-9]+}}(%rsp)
-; X64-SSSE3-NEXT:    fld %st(1)
-; X64-SSSE3-NEXT:    fisttpll -{{[0-9]+}}(%rsp)
-; X64-SSSE3-NEXT:    fucompi %st(1)
-; X64-SSSE3-NEXT:    fstp %st(0)
-; X64-SSSE3-NEXT:    jbe .LBB10_1
-; X64-SSSE3-NEXT:  # %bb.2:
-; X64-SSSE3-NEXT:    movq -{{[0-9]+}}(%rsp), %rax
-; X64-SSSE3-NEXT:    retq
-; X64-SSSE3-NEXT:  .LBB10_1:
-; X64-SSSE3-NEXT:    movabsq $-9223372036854775808, %rax # imm = 0x8000000000000000
+; X64-SSSE3-NEXT:    setbe %al
+; X64-SSSE3-NEXT:    shlq $63, %rax
 ; X64-SSSE3-NEXT:    xorq -{{[0-9]+}}(%rsp), %rax
 ; X64-SSSE3-NEXT:    retq
   %1 = fptoui x86_fp80 %a0 to i64
@@ -577,29 +565,20 @@ define i64 @fptoui_i64_fp80_ld(x86_fp80 *%a0) nounwind {
 ; X64-X87-NEXT:    flds {{.*}}(%rip)
 ; X64-X87-NEXT:    fld %st(1)
 ; X64-X87-NEXT:    fsub %st(1)
+; X64-X87-NEXT:    xorl %eax, %eax
+; X64-X87-NEXT:    fxch %st(1)
+; X64-X87-NEXT:    fucompi %st(2)
+; X64-X87-NEXT:    fcmovnbe %st(1), %st(0)
+; X64-X87-NEXT:    fstp %st(1)
 ; X64-X87-NEXT:    fnstcw -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    movzwl -{{[0-9]+}}(%rsp), %eax
-; X64-X87-NEXT:    movw $3199, -{{[0-9]+}}(%rsp) # imm = 0xC7F
-; X64-X87-NEXT:    fldcw -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    movw %ax, -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    fistpll -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    fldcw -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    fnstcw -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    movzwl -{{[0-9]+}}(%rsp), %eax
+; X64-X87-NEXT:    movzwl -{{[0-9]+}}(%rsp), %ecx
 ; X64-X87-NEXT:    movw $3199, -{{[0-9]+}}(%rsp) # imm = 0xC7F
 ; X64-X87-NEXT:    fldcw -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    movw %ax, -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    fld %st(1)
+; X64-X87-NEXT:    movw %cx, -{{[0-9]+}}(%rsp)
 ; X64-X87-NEXT:    fistpll -{{[0-9]+}}(%rsp)
 ; X64-X87-NEXT:    fldcw -{{[0-9]+}}(%rsp)
-; X64-X87-NEXT:    fucompi %st(1)
-; X64-X87-NEXT:    fstp %st(0)
-; X64-X87-NEXT:    jbe .LBB11_1
-; X64-X87-NEXT:  # %bb.2:
-; X64-X87-NEXT:    movq -{{[0-9]+}}(%rsp), %rax
-; X64-X87-NEXT:    retq
-; X64-X87-NEXT:  .LBB11_1:
-; X64-X87-NEXT:    movabsq $-9223372036854775808, %rax # imm = 0x8000000000000000
+; X64-X87-NEXT:    setbe %al
+; X64-X87-NEXT:    shlq $63, %rax
 ; X64-X87-NEXT:    xorq -{{[0-9]+}}(%rsp), %rax
 ; X64-X87-NEXT:    retq
 ;
@@ -609,17 +588,14 @@ define i64 @fptoui_i64_fp80_ld(x86_fp80 *%a0) nounwind {
 ; X64-SSSE3-NEXT:    flds {{.*}}(%rip)
 ; X64-SSSE3-NEXT:    fld %st(1)
 ; X64-SSSE3-NEXT:    fsub %st(1)
+; X64-SSSE3-NEXT:    xorl %eax, %eax
+; X64-SSSE3-NEXT:    fxch %st(1)
+; X64-SSSE3-NEXT:    fucompi %st(2)
+; X64-SSSE3-NEXT:    fcmovnbe %st(1), %st(0)
+; X64-SSSE3-NEXT:    fstp %st(1)
 ; X64-SSSE3-NEXT:    fisttpll -{{[0-9]+}}(%rsp)
-; X64-SSSE3-NEXT:    fld %st(1)
-; X64-SSSE3-NEXT:    fisttpll -{{[0-9]+}}(%rsp)
-; X64-SSSE3-NEXT:    fucompi %st(1)
-; X64-SSSE3-NEXT:    fstp %st(0)
-; X64-SSSE3-NEXT:    jbe .LBB11_1
-; X64-SSSE3-NEXT:  # %bb.2:
-; X64-SSSE3-NEXT:    movq -{{[0-9]+}}(%rsp), %rax
-; X64-SSSE3-NEXT:    retq
-; X64-SSSE3-NEXT:  .LBB11_1:
-; X64-SSSE3-NEXT:    movabsq $-9223372036854775808, %rax # imm = 0x8000000000000000
+; X64-SSSE3-NEXT:    setbe %al
+; X64-SSSE3-NEXT:    shlq $63, %rax
 ; X64-SSSE3-NEXT:    xorq -{{[0-9]+}}(%rsp), %rax
 ; X64-SSSE3-NEXT:    retq
   %1 = load x86_fp80, x86_fp80 *%a0
diff --git a/llvm/test/CodeGen/X86/scalar-fp-to-i64.ll b/llvm/test/CodeGen/X86/scalar-fp-to-i64.ll
index 77305f43034..7ed61f8fdc7 100644
--- a/llvm/test/CodeGen/X86/scalar-fp-to-i64.ll
+++ b/llvm/test/CodeGen/X86/scalar-fp-to-i64.ll
@@ -1147,25 +1147,21 @@ define i64 @x_to_u64(x86_fp80 %a) nounwind {
 ;
 ; SSE3_64_WIN-LABEL: x_to_u64:
 ; SSE3_64_WIN:       # %bb.0:
-; SSE3_64_WIN-NEXT:    subq $16, %rsp
+; SSE3_64_WIN-NEXT:    pushq %rax
 ; SSE3_64_WIN-NEXT:    fldt (%rcx)
 ; SSE3_64_WIN-NEXT:    flds __real@{{.*}}(%rip)
 ; SSE3_64_WIN-NEXT:    fld %st(1)
 ; SSE3_64_WIN-NEXT:    fsub %st(1)
-; SSE3_64_WIN-NEXT:    fisttpll {{[0-9]+}}(%rsp)
-; SSE3_64_WIN-NEXT:    fld %st(1)
+; SSE3_64_WIN-NEXT:    xorl %eax, %eax
+; SSE3_64_WIN-NEXT:    fxch %st(1)
+; SSE3_64_WIN-NEXT:    fucompi %st(2)
+; SSE3_64_WIN-NEXT:    fcmovnbe %st(1), %st(0)
+; SSE3_64_WIN-NEXT:    fstp %st(1)
 ; SSE3_64_WIN-NEXT:    fisttpll (%rsp)
-; SSE3_64_WIN-NEXT:    fucompi %st(1)
-; SSE3_64_WIN-NEXT:    fstp %st(0)
-; SSE3_64_WIN-NEXT:    jbe .LBB4_1
-; SSE3_64_WIN-NEXT:  # %bb.2:
-; SSE3_64_WIN-NEXT:    movq (%rsp), %rax
-; SSE3_64_WIN-NEXT:    addq $16, %rsp
-; SSE3_64_WIN-NEXT:    retq
-; SSE3_64_WIN-NEXT:  .LBB4_1:
-; SSE3_64_WIN-NEXT:    movabsq $-9223372036854775808, %rax # imm = 0x8000000000000000
-; SSE3_64_WIN-NEXT:    xorq {{[0-9]+}}(%rsp), %rax
-; SSE3_64_WIN-NEXT:    addq $16, %rsp
+; SSE3_64_WIN-NEXT:    setbe %al
+; SSE3_64_WIN-NEXT:    shlq $63, %rax
+; SSE3_64_WIN-NEXT:    xorq (%rsp), %rax
+; SSE3_64_WIN-NEXT:    popq %rcx
 ; SSE3_64_WIN-NEXT:    retq
 ;
 ; SSE3_64_LIN-LABEL: x_to_u64:
@@ -1174,17 +1170,14 @@ define i64 @x_to_u64(x86_fp80 %a) nounwind {
 ; SSE3_64_LIN-NEXT:    flds {{.*}}(%rip)
 ; SSE3_64_LIN-NEXT:    fld %st(1)
 ; SSE3_64_LIN-NEXT:    fsub %st(1)
+; SSE3_64_LIN-NEXT:    xorl %eax, %eax
+; SSE3_64_LIN-NEXT:    fxch %st(1)
+; SSE3_64_LIN-NEXT:    fucompi %st(2)
+; SSE3_64_LIN-NEXT:    fcmovnbe %st(1), %st(0)
+; SSE3_64_LIN-NEXT:    fstp %st(1)
 ; SSE3_64_LIN-NEXT:    fisttpll -{{[0-9]+}}(%rsp)
-; SSE3_64_LIN-NEXT:    fld %st(1)
-; SSE3_64_LIN-NEXT:    fisttpll -{{[0-9]+}}(%rsp)
-; SSE3_64_LIN-NEXT:    fucompi %st(1)
-; SSE3_64_LIN-NEXT:    fstp %st(0)
-; SSE3_64_LIN-NEXT:    jbe .LBB4_1
-; SSE3_64_LIN-NEXT:  # %bb.2:
-; SSE3_64_LIN-NEXT:    movq -{{[0-9]+}}(%rsp), %rax
-; SSE3_64_LIN-NEXT:    retq
-; SSE3_64_LIN-NEXT:  .LBB4_1:
-; SSE3_64_LIN-NEXT:    movabsq $-9223372036854775808, %rax # imm = 0x8000000000000000
+; SSE3_64_LIN-NEXT:    setbe %al
+; SSE3_64_LIN-NEXT:    shlq $63, %rax
 ; SSE3_64_LIN-NEXT:    xorq -{{[0-9]+}}(%rsp), %rax
 ; SSE3_64_LIN-NEXT:    retq
 ;
@@ -1246,37 +1239,27 @@ define i64 @x_to_u64(x86_fp80 %a) nounwind {
 ;
 ; SSE2_64_WIN-LABEL: x_to_u64:
 ; SSE2_64_WIN:       # %bb.0:
-; SSE2_64_WIN-NEXT:    subq $24, %rsp
+; SSE2_64_WIN-NEXT:    subq $16, %rsp
 ; SSE2_64_WIN-NEXT:    fldt (%rcx)
 ; SSE2_64_WIN-NEXT:    flds __real@{{.*}}(%rip)
 ; SSE2_64_WIN-NEXT:    fld %st(1)
 ; SSE2_64_WIN-NEXT:    fsub %st(1)
+; SSE2_64_WIN-NEXT:    xorl %eax, %eax
+; SSE2_64_WIN-NEXT:    fxch %st(1)
+; SSE2_64_WIN-NEXT:    fucompi %st(2)
+; SSE2_64_WIN-NEXT:    fcmovnbe %st(1), %st(0)
+; SSE2_64_WIN-NEXT:    fstp %st(1)
 ; SSE2_64_WIN-NEXT:    fnstcw {{[0-9]+}}(%rsp)
-; SSE2_64_WIN-NEXT:    movzwl {{[0-9]+}}(%rsp), %eax
+; SSE2_64_WIN-NEXT:    movzwl {{[0-9]+}}(%rsp), %ecx
 ; SSE2_64_WIN-NEXT:    movw $3199, {{[0-9]+}}(%rsp) # imm = 0xC7F
 ; SSE2_64_WIN-NEXT:    fldcw {{[0-9]+}}(%rsp)
-; SSE2_64_WIN-NEXT:    movw %ax, {{[0-9]+}}(%rsp)
+; SSE2_64_WIN-NEXT:    movw %cx, {{[0-9]+}}(%rsp)
 ; SSE2_64_WIN-NEXT:    fistpll {{[0-9]+}}(%rsp)
 ; SSE2_64_WIN-NEXT:    fldcw {{[0-9]+}}(%rsp)
-; SSE2_64_WIN-NEXT:    fnstcw {{[0-9]+}}(%rsp)
-; SSE2_64_WIN-NEXT:    movzwl {{[0-9]+}}(%rsp), %eax
-; SSE2_64_WIN-NEXT:    movw $3199, {{[0-9]+}}(%rsp) # imm = 0xC7F
-; SSE2_64_WIN-NEXT:    fldcw {{[0-9]+}}(%rsp)
-; SSE2_64_WIN-NEXT:    movw %ax, {{[0-9]+}}(%rsp)
-; SSE2_64_WIN-NEXT:    fld %st(1)
-; SSE2_64_WIN-NEXT:    fistpll {{[0-9]+}}(%rsp)
-; SSE2_64_WIN-NEXT:    fldcw {{[0-9]+}}(%rsp)
-; SSE2_64_WIN-NEXT:    fucompi %st(1)
-; SSE2_64_WIN-NEXT:    fstp %st(0)
-; SSE2_64_WIN-NEXT:    jbe .LBB4_1
-; SSE2_64_WIN-NEXT:  # %bb.2:
-; SSE2_64_WIN-NEXT:    movq {{[0-9]+}}(%rsp), %rax
-; SSE2_64_WIN-NEXT:    addq $24, %rsp
-; SSE2_64_WIN-NEXT:    retq
-; SSE2_64_WIN-NEXT:  .LBB4_1:
-; SSE2_64_WIN-NEXT:    movabsq $-9223372036854775808, %rax # imm = 0x8000000000000000
+; SSE2_64_WIN-NEXT:    setbe %al
+; SSE2_64_WIN-NEXT:    shlq $63, %rax
 ; SSE2_64_WIN-NEXT:    xorq {{[0-9]+}}(%rsp), %rax
-; SSE2_64_WIN-NEXT:    addq $24, %rsp
+; SSE2_64_WIN-NEXT:    addq $16, %rsp
 ; SSE2_64_WIN-NEXT:    retq
 ;
 ; SSE2_64_LIN-LABEL: x_to_u64:
@@ -1285,29 +1268,20 @@ define i64 @x_to_u64(x86_fp80 %a) nounwind {
 ; SSE2_64_LIN-NEXT:    flds {{.*}}(%rip)
 ; SSE2_64_LIN-NEXT:    fld %st(1)
 ; SSE2_64_LIN-NEXT:    fsub %st(1)
+; SSE2_64_LIN-NEXT:    xorl %eax, %eax
+; SSE2_64_LIN-NEXT:    fxch %st(1)
+; SSE2_64_LIN-NEXT:    fucompi %st(2)
+; SSE2_64_LIN-NEXT:    fcmovnbe %st(1), %st(0)
+; SSE2_64_LIN-NEXT:    fstp %st(1)
 ; SSE2_64_LIN-NEXT:    fnstcw -{{[0-9]+}}(%rsp)
-; SSE2_64_LIN-NEXT:    movzwl -{{[0-9]+}}(%rsp), %eax
+; SSE2_64_LIN-NEXT:    movzwl -{{[0-9]+}}(%rsp), %ecx
 ; SSE2_64_LIN-NEXT:    movw $3199, -{{[0-9]+}}(%rsp) # imm = 0xC7F
 ; SSE2_64_LIN-NEXT:    fldcw -{{[0-9]+}}(%rsp)
-; SSE2_64_LIN-NEXT:    movw %ax, -{{[0-9]+}}(%rsp)
+; SSE2_64_LIN-NEXT:    movw %cx, -{{[0-9]+}}(%rsp)
 ; SSE2_64_LIN-NEXT:    fistpll -{{[0-9]+}}(%rsp)
 ; SSE2_64_LIN-NEXT:    fldcw -{{[0-9]+}}(%rsp)
-; SSE2_64_LIN-NEXT:    fnstcw -{{[0-9]+}}(%rsp)
-; SSE2_64_LIN-NEXT:    movzwl -{{[0-9]+}}(%rsp), %eax
-; SSE2_64_LIN-NEXT:    movw $3199, -{{[0-9]+}}(%rsp) # imm = 0xC7F
-; SSE2_64_LIN-NEXT:    fldcw -{{[0-9]+}}(%rsp)
-; SSE2_64_LIN-NEXT:    movw %ax, -{{[0-9]+}}(%rsp)
-; SSE2_64_LIN-NEXT:    fld %st(1)
-; SSE2_64_LIN-NEXT:    fistpll -{{[0-9]+}}(%rsp)
-; SSE2_64_LIN-NEXT:    fldcw -{{[0-9]+}}(%rsp)
-; SSE2_64_LIN-NEXT:    fucompi %st(1)
-; SSE2_64_LIN-NEXT:    fstp %st(0)
-; SSE2_64_LIN-NEXT:    jbe .LBB4_1
-; SSE2_64_LIN-NEXT:  # %bb.2:
-; SSE2_64_LIN-NEXT:    movq -{{[0-9]+}}(%rsp), %rax
-; SSE2_64_LIN-NEXT:    retq
-; SSE2_64_LIN-NEXT:  .LBB4_1:
-; SSE2_64_LIN-NEXT:    movabsq $-9223372036854775808, %rax # imm = 0x8000000000000000
+; SSE2_64_LIN-NEXT:    setbe %al
+; SSE2_64_LIN-NEXT:    shlq $63, %rax
 ; SSE2_64_LIN-NEXT:    xorq -{{[0-9]+}}(%rsp), %rax
 ; SSE2_64_LIN-NEXT:    retq
 ;